I'm an OSHA trainer/ instructor I've heard lots of trainings in my time, this is one of the best detailed well said instructions/explanations I've ever heard if your not in the field of helping others you should be I can tell by your presentation you make one hell of a guy to do so your voice carries perfectly your deminer is calm dude you got a gift thank you for helping all us ... very very impressed.
Great video thanks for the help on mine it was the 4 injectors after replacing everything else i wished i could have found your channel before i did all that thanks again God bless
I'm amazed at the many attempts to fix this that had no effect. Guess you go with the easiest things/cheapest things first, so no one wanted to dive into the fuel pump as a possibility . Good video.
It's because the fuel system is continuously wearing down but it is not a material problem functionally until the engine throws a code at around 200-300k. Meanwhile, you lost gas mileage without knowing it for about 100-200k of driving.
I was reading your subtitles, realized I had to watch the vid 👍 I've been dealing with a p0171 since 2019 when I bought my 03 MB C230K coupe as a project car for my gf... I replaced the fuel pump yesterday, the dealer had replaced the pump in 2010 but my code is intermittent so I had a specialty shop clean my MAF sensor, passed smog recently and I didnt need an upper oxy sensor and my cat is good. I replaced the coil pak, plugs, purge valve (the shop didnt catch it) after repl. the gas tank filler neck leak (typical w/2005 model)... I bought this m271 engine because the hoses were like new until the lower radiator hose broke from the manuf. clamp/age. I currently have a EGR valve hose that inexplicably got a razor like slit after it got smogged. I wasnt showing the p0171 code so I just taped it up and heat taped it but I've never ran a pressure test on it just went underneath and took a scope to the engine to inspect the hoses as I keep them up. Post fuel filter replacement I showed a p0301 misfire cyl 1 after I swapped around the coils and plugs. Cleared the DTCs, it coughs sometimes when started but seems to have a hard start or kick like sensation felt in the pedal. I bought the injector for cyl 1 last June but the fuel additive seemed to have done the trick the last six mos. The car purrs along at 33 mpg hwy, 27 mpg city, handles hills, hard to see that I have compression issues. Gonna replace all 4 injectors and go from there. Might buy a new fuel pump, we shall see. I shoulda just put in a new MAF sensor but the shop was hesitant to put in any new parts I bought so I dont go there anymore. I caught more dirt in the engine this summer compared to last year.
If you can run a fuel pressure test before replacing the fuel pump. Low pressure can be caused by a bad pressure regulator or clogged filter among other things.
Found my problem of a dirty MAF sensor... used MAF cleaner to clean the sensor two tiny silver wires that were heavy coated with dirt, clear the code, no problems, truck run great 👍...
Common sense is to replace or clean any cheap [arts first: plugs, coils, injectors, clean MAF sensor, replace TPS (not worth trying to clean), replace air filter, check for cracks or leaks. THEN get help from a competent mobole mechanic who knows the patterns for an old car like yours... An old Corolla will be very well known to mechanics.
Thanks for the great tips, I'm working on this issue on a 04 Camry at the moment went through all the minor steps, fuel pressure is the next move to verify it's in the right range.
Solved my p0174 & p0171 with 4 cans of Lucas injector cleaner. Took awhile to go through 4 tanks but light is off now. Checked by a mechanic and he said it's not throwing those codes anymore.
Great informational on the lean fuel code issues! You hit every bullet point dead center. This is the first video Ive seen of yours, but can guarantee I'll be looking through more for help along the way. I drive a 1st gen Expedition 4x4, and have same lean code. My issue is the front wheel hubs bring more unregulated air into the system. Great video and look forward to learning some more wisdom for Your Car Guy DR! Keep us Rollin 🛞
@Your Car Guy DR. i have a 2003 Camry with 540k miles my first ever car still running like a Gem. after replacing the Evap Canister i noticed i was gettting the P0171 checked ALL the air intake sensors hoses etc. .. issue Fuel pump. thanks for helping GPA car get back on thr ROAD
Turns out it wasn't my air filter. The check engine light would sometimes go away on its own. Even after replacing both oxygen sensors, MAF sensor, headcover gasket, and smoke testing, air filter, the code kept coming back. I later discovered that my fuel injectors were in pretty rough shape. The housings were cracked, but visually nothing was clogged. I didn't really have a way of testing them, but my '02 corolla is at 230k miles, and believe they've never been replaced. So I've replaced the fuel injectors, and the car runs and accelerates a lot better now; it even starts up faster and possibly better mileage. It also has cleared the P0171 code, but I will have to drive the car a bit longer to determine it. If anyone is still having this code, I think it's worth replacing the fuel injectors. Just be careful working around gasoline, and make sure to get Denso OEM injectors. They do run a bit expensive 130$, but you won't have to worry about getting the O-rings.
I replaced my 2002 4Runner with Beck & Arnley fuel injectors. They’re the same oem fuel injectors I believe just remanufactured? Don’t quote me on that but they reuse the Aisin oem fuel injectors 100%
Oh wow. My 2000 Toyota Corolla it has the check engine light on PO 171 . And sometimes will say misfire on cylinder number 2. And I reset the light drove it pass the emissions and right away after I drove away from the shop light came back. I reset it few times and keep coming. So this is amazing video I’m going to look for that diagnostic
Very informative. Thanks. The fact the dealer just threw parts at it is pretty disheartening and disgusting. Of course they charged for all that unneeded work.
I'm gonna put in work on an 07 Corolla and this code is one of them beside the p0420 which is a bad cat but. I'm hoping it's the maf or 02 sensor. But thank you for this video helped a lot.
Warning about those kinds fuel assemblies. I'm not special mechanic but there's like a sponge like thing inside the assembly (at least in mine there was), if there's a lot of miles on it, I'd go the expensive route and get the whole assembly. I took apart the assembly and went the cheaper route and just replaced the pump and filter. Then I discovered the sponge stuff inside, took out the fuel pressure regulator, I put a small piece of hose to where the fuel pump goes, I blew some fluid through with a squeeze bottle, the fluid was blackish silver. This only happend when I took it apart though. When doing a fuel volume test, the fuel looked clean. So I'm assuming something faulty with sponge thing as well. My car also passed the fuel pressure test but did not pass the fuel volume test.
Great video. Fuel pump is my problem as well. P0171 code, lean bank 1 (4 cylinder only has bank 1). 2016 Turbo Dart. looked high and low for vacuum leaks. This video confirmed my fuel pump suspicion. I replaced the original fuel pump with a Delphi unit 4 months ago. To verify the new pump is at fault I had to rig up pressure gauge in the fuel line. No pressure test port from the factory. And what do you know, 37 psi when should be 58 psi, and drops to 0 when engine is shut off.
A bad EVAP system can also create a lean code. Disconnected the EVAP purge solenoid and drivability greatly improved and no more lean code. Yes, EVAP code was still there.
Wow! Thanks for your descriptive video. I’ll check the fuel psi on my 97 Camry and the fuel filter. Bought the car used and not sure if the filter has ever been changed.
i have a 2001 Toyota corolla S with 80,000 original miles , I have only the P0171 system too lean bank 1 , I changed out the mass airflow sensor after cleaning it good the CEL came back on , after changing out the 85 dollar new mass air flow sensor , cleared the code , drove 50 miles on the freeway , no more CEL , now time for a star smog test in So CaL .
Thanks for the vid i have a feeling my 08 xb may have a fuel pump issue got the car with 180,000 might have to check the pump a lot of the parts on this car seem original🤔🤔🤔
Corollas are known for having this code 00-10. I already owned 2 corollas one 03,06 and they both had that issue. My experiences were that the code only came up when the weather got cold. Most of the times check engine light would turn off itself by the end of the day. The mainfold gasket is the main reason that causes this.
Intake manifold or exhaust manifold? I just replaced both so I couldn’t pin point which one it was however I believe in my case it was the exhaust manifold
The reality is that the fuel delivery system is experiencing continuous wear but the computer cutoff for when Toyota wants the customer to address it is much later than when the condition originally occurs. Clogging of the injectors can begin as early as 60-100k but nobody drives with an OBD scanner monitoring longitudinally the change in long term fuel trim. The gasket would create a lean vacuum leak. In that case the engine calls for more fuel at idle and decreases the extra demanded amount as the throttle body opens The fuel system degradation would cause a lean code after the engine is pushed. Meaning LTFT increases with more acceleration.
I have the same code for my corolla 2003 !! I take it to toyota dealer and they want to charge me 1100 dls for change the manifold ( they crazie ).. the word part is they told me that they not sure that fix my problem
Accept that most dealers and mechanic shops make money selling parts. The labor is not a money-maker. I found 2 mobile mechanics and have a "fall-back" if 1 is unavailable and never quibble about their labor cost and if they are willing to explain or show me what they are doing... I pay close attention. That's how I learned to set up electric guitars and now I can do nearly all of it myself. Basic tools and knowledge is all it takes and it can save a lot of annoyance. .
We sell our parts at the same cost available to you when you shop at automotive parts retailers. Stop spreading false information. Labor is a 50/50 split. You when some you lose some. You Never know what youre gonna run into during a job.
My Toyota V6 was doing same thing replaced everything MAF, Oxygen Sensors, throttle disassembly and cleaning to dealership no avail only thing that worked was several aggressive treatments with Cheveron fuel injector cleaner just got it to pass smog. Might have to drop tank.
IF you see that code on the Chevy 1.4L Turbo found in the Chevy Sonic, or Chevy Cruze, AND the 1.8L non-turbo...a great place to start is the plastic valve cover gasket. The design is the failure point. No more than $210 for the part, and with a torque wrench, an easy fix.
Some good info, and insight, on this problem. Thank you! My 02 Tacoma started acting up last night (Check engine light came on....then it didnt want to maintain idle, and would fall off flat at WOT on the way home). Luckily, it's a manual trans, or AAA would have encompassed the rest of my evening. Interestingly, I had JUST dumped a bottle of Dry Gas (with injector cleaner), in it yesterday because of all the temperature swings, and rain we've had on the East Coast, lately. Hrrrmm Limped it home, and pulled the engine codes : PO171, and PO136. I'll start with the O2 sensor, check for vacuum leaks, and move on from there. If fuel pressure is at spec, and the injectors are all at their respective factory specs for resistance, do you think a clogged CAT could contribute to this issue in any conceivable way? Thanks for any reply, and your time. "Liked, and subbed." 👍
If it just started happening after the dry gas was added I would try to get to a second tank of fuel and see if it clears up. Clogged catalytic converters are pretty rare.
Great post I got a p0171 lean code so I will check my fuel pressure before I spend money on parts I dont need ps why would anyone take a beater car to the dealer lol they will charge you more than the car is worth it self lmao
Running in low fuel regularly leads to fuel filter issues...because the whole unit is built into the tank..it's best not to dip too low past the quater mark
Been getting P0171 but mostly when it's cold and within a few minutes of starting. Checked with vacuum gauge and it was normal, but did that test on a warm day and in semi direct sun. No abnormal idle that I can see. Then I did a fuel pressure test. Used rubber adapter and brass fitting which came with the gauge to connect the gauge hose to a T adapter. Start engine and it reads steady 40. Then I noticed that the pressure pushed the hose half off the brass fitting and there's a strong stream of gas spraying inside the engine area. Checked all connections in case I didn't have it right. The hose fit well and snug on the knurled teeth of the brass connector. Start up again and it pushed the hose about half way off and again gas spraying out steady, and reading 40 again until I quickly turned it off. My question is: If the pressure is 40 with this much gas spraying out, do you think actual pressure is probably in the normal range? If so, then with the code happening in he cold, all I can think of is to replace the intake manifold gasket. What do you think?
same on my corolla 06 p0171 no leak nothing. engine stalling in summer above 30 celcius I waited 5 minutes and the car started again 3 time this summer and if I leave the air conditioning on the idle in summer after 10 minutes the engie stall on its own but works very well in winter but only have bad cold idle they work like a camed car lol but after the car runs very well for all the winter I did everything ... I have the car for 2 years it had the code p0171 since purchase written on the obd2 305 000km... clean maf check o2 sensor up and down collant refill fan perfect temp perfect 86c in summer radiator perfect no leak no intake leak no smoke dozen burn oil no code when stall no code when stall no code when run like a cammed car
mckoy lach you are correct. A clogged fuel filter will result in low fuel pressure along with decreased flow and thus causes a lean condition. As the filter is built into the fuel pump assembly on this car the repair process is very much the same.
That’s right these car dealership can take your money and they still didn’t fix the problem you should sue and get your money back they are money hungry I have the same problem and things you don’t need and you only going because your check engine light on I will never do that again try and fine the right mechanic that knows what he’s doing or ask a good friend where they take there car that they can recommend never go to a car dealership.......
I have a 1997 Lincoln Town Car has the same codes with a check engine light on. Drives great around town. but on the highway cruise control set to 68 miles per hour the second I hit a hill incline the car will downshift to boost power but has no pep at the same time the po171 and po174 codes and engine light kick on if I have cleared the codes prior to this test run. With possibilities being from an O2 sensor vacuum leak or fuel pressure where do I begin. NOTE my scanner shows me my battery volts from the OBD2 port connection is reading 12.5 volts compared to other vehicles at my disposal that's almost 2 volts less could this be causing poor fuel pressure not having ample power to the fuel pump
Claudio Fagundes as long as you are over 12 volts you are fine. Since you are getting both the p0171 and p0174 I doubt that your issue is an oxygen sensor. I would check for vacuum leaks. I would also do a fuel psi test.
my Avalon 02 had same code to lean, checked lines good, but car only turned on to a bogle off. then i removed the air filter and car turned on so just got a new engine air filter in there and its all good now.14$
Great vid!👍🏻I Hava po171 code primarily in the winter. The car purrs - no symptoms whatsoever. Should I do a fuel press test? If it is a pump prob, can I swap out the fuel filter Only,i’m guilty of driving around w/ low fuel levels😅
How can i fix a p0172 problem on a 99 toyota tacoma 3.4 v6. Any suggestions please comment i already replaced coils, spark plug wires and spark plugs and code still pops up. Please comment below. Thanks for the help in advance.
Well I do have this code but I don't think it has anything to do with the fuel pump or fuel filter because I replaced both of them twice within 3 months. But the code was actually reading p0340. Not a camshaft position sensor. I don't care what anybody says. That is a bad fuel pump. Because even after I replaced the camshaft sensor with that code it didn't start. It was a fuel pump. It's common sense if you don't hear the fuel pump buzz. It's bad. My car has been having trouble starting like as if the fuel pump was bad. My car has had a fuel system problem even before the fuel pump went out and ever since I replaced the fuel pump fuel filter the gas cap p0440 And the O2 sensors p0171. The issue is still happening. The engine hesitates to start due to lack of fuel. It's not the spark plugs or air. I know that for a fact. Like I said my car has had a fuel delivery system for a while now. I've been replacing a different part each month. I'm really hoping that it's not a bad timing chain because that can cause a car to have these exact issues as well. Most of the time when my car starts it starts right away but it has like a 1 or 2-second delay. But still starts right away. P0171 bank 1 running too lean Can cause a car to stall hesitate And hesitate to go up a hill or from a complete stop. And most definitely feel like the transmission is sifting hard. My car has a lot of issues but I'm starting to think That the po171 and p0440 Is a blown head gasket because it's leaking oil. That's the only other thing I can think of besides a bad timing chain or a bad fuel injector. But I hooked up three different scan tooland 1 says PO171 bank 1 running lean. And the other scan tool says P0171 O2 sensor heater circuit malfunction. And the 3rd one say p0440 and p0171. Large Evap leak and bank 1 running lean. And no seafoam does not work. That is a bunch of crap. It only made things worse. Trust me and those fuel injector cleaners don't work either or the fuel system cleaners. Problem with the fuel system. None of those feel additives are going to work. Trust me, it's common sense. Tired of wasting money. Trying to figure out what the issue is. But you mentioned head gasket leak and I think that is the only thing that it could be besides a timing chain. Because The engine is leaking oil. And it's leaking onto the exhaust causing the car to sting under the car, not under the hood. So if my car is leaking oil it could very much be a head gasket leak and can leak oil on other metal parts including the timing chain. You are definitely right about people not checking for fuel pressure, but people also don't check the timing chain that has a lot to do with it too. But I know for a fact it's not the fuel pump on my car or the fuel filter cuz I replace those things twice.
Hello, I recently allowed myself to get scammed and purchased an 02 Corolla that had this hidden P0171 Code & a salvage title among other issues. They had disabled the check engine light so that it wouldn't come on. Anyways, I am trying to learn as much as I can about this PO171 issue and I suspect it is a fuel delivery problem as well, for this specific vehicle. Upon watching your video, I tried to locate where I could connect a fuel pressure gauge, but as far as I can tell, the area in which you showed in this video, does not disconnect from the fuel rod. It is withstanding the force of simply pulling the line off. In case anyone reads this comment, where exactly do I connect the fuel pressure gauge & where can I buy this 02 Corolla adapter kit necessary to establish this connection? I cannot locate a kit for this make/model online. Thank you regardless for your informative video.
I have a 2000 model which looks pretty much the same, if I remember correctly we might've taken that fuel hose off at the end closest to the engine. Might be worth a try but I don't know what I'm doing, I know we checked fuel pressure though.
There is a connection coming from near the firewall to the engine. It requires a special line tool to release. You can get a fuel pressure test kit that will have the needed adapters. If I remember right my kit was around $100.00 online. Not name brand but it works for the times I need it.
The last time I did this the entire assembly was expensive, however the individual parts are not. You can do it either way depending on your budget and desire to do the little bit of extra assembly. I would recommend changing the filter either way.
AVRAHAM BREA the intake manifold gasket was changed during the head gasket job the dealer did. As much as I have heard that it is a common failure on these engines none of the ones that I have run into have had intake gaskets leaking.
I have a 2000 Corolla... replace all 4 injectors as a good start and new NGK platinum plugs with 4 coils. Routine stuff and any 'mobile mechanic' can do it cheap.... you buy the correct parts and hire him to install them!
How were you sure it was the injectors? My 2000 is at 180k so it could be that, but I don't like throwing parts at things. That's how yo incorrectly replace head gaskets, as was mentioned.
@@girohead I replaced injectors at about 220K miles at the advice of a skilled mobile mechanic (worked on racing cycles and cars) who has a sophisticated scanner. A 'miss' I resolved this year with 1 'ignition coil wire' for about $70 and 2 minutes time ...
haha the dealer just shotgun parts in attempt to fix it. i work at lexus and im still scratching my head i have an 2003 matrix 1zzfe. fuel pressure check is next followed by smoke the engine to see if i can find any vacuum leak. i already replaced intake manifold gasket per service bulletin. car was fine before i put in new clutch n flywheel. no kinked lines from removing subframe and my wiring grounds are solid.
Thanks for this video. The other day I was on a hill and the car was in reverse and I didn’t realize… I took my foot of the brake and it started rolling forward. I went to step on the brakes and it was stiff and all of the lights on the dash board came on…. i quickly put the car in neutral and turned it off for a few and it drove fine. Now i notice the brakes get stiff and dont grab if i ‘pump the brake pedal’ several times and now my Check engine, vsc and other light came on. I have the code P0171… could this incident cause a P0171? any idea why this would happen or did this lean fuel code just happen to come on coincidently from a separate issue? any help you can offer is appreciated.
This is most likely coincidence. The brakes and the P0171 are likely not related unless you have a massive vacuum leak. The brake booster works off of vacuum on most vehicles.
The fuel pressure can be affected by several things. First if the fuel filter is plugged. Next if the pickup screen is plugged. Next would be the fuel pressure regulator. If all of those are fine and the pump isn’t producing adequate pressure or volume then the pump needs to be replaced.
i noticed the older 4 runner there.. i have a 1995 4runner 3.0 3vz getting code 25 running lean and i have checked all my vacuum hoses.. now its running horrible in the mornings and rough through the day... at its worst im hitting the gas and its just chugging up and down RPMs.. wants to stall at a stop while in drive.. but revs up fine while in Neutral or Park.. sounds fine too... any suggestions .. also notice the dash lights dim a little when windsheild wipers are moving/blinker blinks/ or when i tap on the breaks.. normal? also i just changed the EGR.. was getting that code aswell
OBXTarheel91 the lights sounds like a bad ground. Check your battery cables and especially check the grounds where they connect to the frame. This can also cause some engine issues. There are several grounds that go from the body to the engine. If these are bad or corroded clean them up. The running lean can be caused by low fuel psi just like it was for the car. A good upgrade is to replace the injectors with a 4 hole style. You can get a matched set online at a great price. I am currently doing a rebuild on the engine for that 4 runner (same year and engine as yours).
Mario Torres yes any decent shop should be able to do a fuel pressure test. They can also take a sample of the fuel if needed to have it tested in case you got a bad batch of fuel.
Injectors don't affect fuel pressure. They certainly can be clogged and cause a lean condition. Pump or regulator. Even a clogged fuel filter would have to create a massive drop in flow to affect pressure.
Gregory Fairchild I am guessing you have never seen a leaking injector or injector that has worn to the point of severe over fueling. As a certified master tech with more than 20 years of experience I have seen this on multiple vehicles from multiple brands
@@YourCarGuyDR Wouldn't a leaking injector,or over fueling injector, cause a rich condition, or even a misfire? I would think you might even end up with fuel in the oil that would also contribute to a rich condition. Some basic diagnostics by the dealer should have found this easily...I would think this would have exhibited relatively normal, or just slightly positive fuel trims at idle that got worse with RPM and/or load. A wide open throttle run while watching the O2 would have shown the O2's go lean...that really only leaves a MAF (which the dealer totally guessed on) or fuel delivery. Can't believe they did a head gasket. That's just malpractice.
@@YourCarGuyDR Do you think the 23 gas mileage on my 01 corolla is the cause of the mass air flow sensor. There is just p0420 code pending and fault. Idk why the car get bad gas mileage. Its a 2001 toyota corolla ce, 3 speed automatic.
@@YourCarGuyDR yea, Im beginning to think its just the 3 speed automatic, so the car never goes into overdrive. However even in the city its bad gas mileage. So idk.
Hi, where do you buy the injectors? I have a 2001 corolla and replaced the engine with a 2005. I get a p171 trouble code at 3mph at 700 rpm idle. Would I get the 2005 injectors or 2001? Also knocking under steep uphill. Ive replaced both o2s, cat and fuel pump. I will test for vacuum leaks with a smoke machine. Car has 300k miles. Thanks in advance.
This can be a bit of a dilemma. If you are using the 2001 computer you will likely want the 2001 injectors. The knocking may be caused by a fuel issue but can also be a timing issues or a bad bearing. One other thing to be aware of is that there may have been a change in the camshafts between the two years. This could included differences in variable cam timing. If possible you would want the computer to match the year of the engine. I have in the past on these cars put the older cam in the newer cylinder head since I was running the old computer. As far as purchasing injectors I usually search online and be sure to look at reviews and verify that you are getting what you pay for.
@@YourCarGuyDR thanks again. I only get the misfires like twice a year when i go to Victorville. But all around it gets great milage and good power. I just need fix the code before my next smog check. I dont have the original camshaft anymore, but thats a good point. Maybe ill find a vacuum leak.Thanks
Hi there. I got the same diagnostic. Because i think a mecánic took the second heater core out without my permittion. I only have one heater core which heats in cold weather. Do you think is that the problem. He also change my maf sensor and this issue started. Reads code P0300 that im having issues with my maf sensor now. But know they ran another diagnostic. 2 weeks after maf sensor didn't show. But im getting a most likely manifold gasket. Auto parts told me you might have a vacuum leak. Could it be Because my reservoir container underneath i have a leak?
I’m going to try this on my 350z I have had that code for a couple months now and today heading home from work it dropped rpms and didn’t want to a accelerate when I step on the gas.