Engine Misfire - Top 5 Causes  

This is all true, but video was about top 5. Good info for others, Thanks!

Could be shitty gas we are getting now

@@BraidenMaleterre-gb7zvjust refilled in nevada and check engine light came on and now my cars knocking 😂 sounds and feels like a cammed american muscle

Sign crankshaft /camshaft sensors

@@jrhernanadez1855you’re the only one who would put a laughing emoji after saying you car was knocking 😂

I guess you didn’t watch or understand the video.

Thank you!, Yep dealerships only want to do easy warranty work. Most don't know how to diagnose properly mainly because they are under pressure and time restrant.

Yes, this is true.

How to fix and cost to fix?

That’ll give you a misfire for sure!

Oh maybe that the case in my Lexus Rx I found signs of rats can't be fixed yet

How much did it cost to fix

Oh I didn't fixed yet mi mechanic said lost pressure in cylinder #1 so he recommended to switch a engine better the car are running good except when stopped and to pass the inspection it doesn't go to pass

If timing is off will result in low cylinder compression as I stated in the video.

do you think a misfire will occur if i use 87 when the requirement is 93?

@aquaticwavess2909 if the vehicle requires a higher octane then, yes

What if I mixed a qtr of 87 with the rest 89

91 would be better and should be fine

This is true, but this is top 5 , not all causes.

Thank you!

This was on the top 5, your is not that common

Thank you!

Yes, resulting in low cylinder compression. Like I just stated.

Thanks

What codes are coming up?

Can be many things like bad fuel pressure, vacuum leak sticking valves etc. should check cylinder compression when cold and hot when misfiring to see if it’s the valves.

If its a honda 6 cylender with high milege cuold be the valvs to tight or crank senser or a jump timing chain.or high presure feul pump cam roler worn out.

If its a honda 6 cylender with high milege cuold be the valvs to tight or crank senser or a jump timing chain.or high presure feul pump cam roler worn out.

Correct! I have other videos explaining just that! Thanks

It can

Sounds to me like a vacuum leak, start there

I have the same problem. Pls let me know once you fix it. Thanks

Yes, I have videos that explain that.

Yes, I made many videos on everything that goes wrong with these engines.

It very well can cause misfiring.

@@Motorcarnut so if you change the spark plugs again, should be good then eh for couple of weeks 😄?

No, the tuning sounds like it’s causing the misfiring?

Number 2 cylinder I would check cylinder compression, should be minimum 90 psi then I would check fuel injector for operation.

Can be anything then, got to reinstall the plastics first or you’ll be chasing problem after problem

Sorry, it can be as little as $100.00 up depending on what is exaclly wrong and how much the labor is. It's too broad to know. And I don't know what is your particular problem.

@@Motorcarnut thank you, the Mechanic today charged me $260 for my spark plugs on a 2017 Honda Accord. My vehicle has more than 200k milage and it runs perfectly fine.

​@@RiNiSMspark plus wire literally just plug in and out. More research before spending money unless its engine related/urgent. wires only cost like $70

$100 to $7000 according to some scamechanics😂

What codes are coming up?

Oh man, who would check that? Wow that stinks

Yes, but rare.

What codes are coming up?

@@Motorcarnut misfiring codes. I had the pictures of the numbers but then deleted them. So I have to do it again and I’ll tell you. I’ll do it today

If you're willing to spend the money on coils, why not take it to a shop and get a real diagnosis instead of throwing expensive parts at it? It could be something way outside of the system you're looking at

@@KekeeBlack I found out what it was. It was my injectors. They were dirty. So I used liqui moly on in my gas tank and solved that problem within minutes. Now I got to do something about losing coolant lol has to be a hose or something that’s leaking

No, lower octane yes but not higher. Higher octane controls combustion more efficiently.

You seem confused. Vacuum leak will cause a lean condition resulting in misfires. Most vehicles today don’t have ignition wires but you’re correct on that one.

Here's another reason for a misfire... Gene Ortiz goes down to Bombay Fuels every few days for that cheap $2.99 regular and you get something in the gas tank that isn't exactly gasoline or ethanol 😆.

See which cylinder is misfiring and switch coils to see if the misfire jumps. If it does than you know it’s the coil, if it doesn’t then can be spark plug, fuel injector or low cylinder compression

Yep, but this vid is about top 5 not all

All can cause a misfire, yes.

That would also cause misfiring yes as well as loss of power.

You have to start with simple and cheaper things first. Check cylinder compression if it’s only one cylinder misfiring cold and hot. I have videos on that as well. Fuel pressure and injector function as well as valve timing which if we’re bad would show up on the compression test.

@@Motorcarnut ok thanks for the reply

No problem

At this point the only thing left is the injectors or ecu but most likely the injector

Being that this happened after oiling the cold air intake it probably massed up the MAF sensor, so I would clean it first to see if that helps.

I did and still nothing. Could be plugs, coils or bad valves​@Motorcarnut

When it’s custom tuned, who knows what went wrong, there are no procedures to follow or to know what they may have did wrong?

@Motorcarnut nothing in the tune it's done professionally. It definitely has to do with the car it's self. Maybe bent valves or dropped rocker, burnt valves. It only happens on full throttle, under 75%it's still really good. Just if I put the peddle down it backfires about 7 times and if I don't let off it misfires the cylinders

Yes it can, but rare

Yes, this was just the top 5 but yes their are many more

​@@Motorcarnut👍

@ChrisQuadFPV thanks

What codes pop up misfire how do you find head is Crack?

@@art-ip4ue sometime a misfire code. But mainly use the blue liquid pump the radiator to see if it turns yellow. And check the oil dip stacks to see if it's milky

You have multiple misfires, can be vacuum related or timing, but has to be diagnosed properly to fine the cause

I wouldn’t recommend it. It puts more strain on the rest of the engine.

A piston that is damaged, yes.

@@Motorcarnut yea I took it to my mechanic an it’s not a piston just the pipes in the bottom

Sounds better than replacing pistons

Yes. A vacuum leak near the misfiring cylinder or all cylinders can come from intake manifold, PCV system etc.

@@Motorcarnut i have a problem when misfire test result 0703 misfire injector 3 , spark plug new ..

If not done already, i'd do a cylinder compression test, what codes are coming up and how many cylinders are misfiring?

@Motorcarnut I don't know it's still at the original shop they said the engine is good and have done everything they could but since they put in the ecu it started misfiring and shaking, they said there is a guy that has the equipment to diagnose more detail I'm hoping it will be towed there Monday.

First thing you should do is check cylinder compression on all cylinders. Should have over 100 psi on each. Do a cold test then a hot test to rule out sticking valves or valve timing problems. I have videos on doing compression tests if you don’t know how to do it. I wouldn’t throw more parts at it. Also, a blinking check engine light is bad, will destroy the catalytic converter if you keep driving it.

Have to see which cylinders are misfiring, what codes are coming up?

Rpmz idle low and high? Check your mas air flow sensor or throttle body is going bad

Replace it. But they rarely go and are expensive so make sure that’s your problem

Yes, creating a vacuum leak which will give you a misfire.

Have no idea what vehicle you have but probably a vacuum leak somewhere.

@@Motorcarnut thank you I will check with water spray, it's an xterra if that changes anything

@coolghoul9 No, it doesn’t, good luck!

If this happened after you replaced the head it's hard to tell what you did wrong? Did you check the new head and cylinder block for straightness? Do a leak down test on all cylinders to make sure valves are sealing properly. Any codes coming up?

@@Motorcarnut I also replaced the valve seals. No oil leakage, Engine light on but was deleted. My mechanic says it could be problem with the Nosals. What do you think?

Again, if you didn’t have this problem before I doubt it

Yes, but those are the most common

Possibly, but low power output would be the biggest symptom for a clogged cat.

Can be, sure, but this was top 5

Has to be diagnosed with a scan tool under load to see what’s going on with it.

I have the same issue on my c200 cgi. Will share the codes after scanning

Definitely do a cylinder compression test, may have a valve sticking etc

@Motorcarnut ooh shit. OK. Didn't think about that. In my head I'm thing king my rings have got to be fine it's low miles. But um ya lol. A vacuum leak sticking off the seat is basically a blow by situation lol. So I'll hit harbor freight for that Guage and I've done this a while back you just pull the injectors fuse and the crank it and you should see like 110 pai ish if I'm not mistaken ?

Correct

@@chriss6154I had 170-175 compression on all my cylinders in my 03 Silverado last time I checked

Yes, sounds like a fuel related problem.

@@Motorcarnut I also Changed the o2 sensor code still in there the high pressure fuel pump is new and it’s also saying cylinder 3 misfire do you think it’s an injector?

Try a cylinder compression test on that cylinder first

@@Motorcarnut compressions good on all cylinders I’m thinking the timing is off a tooth or so also changed cylinder 3 fuel injector same thing actually shot me a Timing code

Very well could be

Did it do the misfiring before the timing belt change? If it didn’t they probably messed up the timing by a tooth.

@@Motorcarnut so I never had the misfire code until after I cleaned the egr cause it was super clogged and check engine light came on and decided to do the timing belt as well same time. But after that got misfire codes. Idk maybe the disturber? Egr port? Pcm?

@ismaelismael7055 what vehicle and engine you working on?

@@Motorcarnut Honda Accord 1996 ex 2.2 liter 4 cylinder

You probably messed up the timing since it happened after the timing belt replacement. Double check valve timing again.

Yes those can make a misfire as well.

Hence top 5

Under the cowl where windshield wiper motor is

It's going into limp mode because of the multiple misfiring. Check for vacuum leaks, valve timing, ignition system and fuel system

I performed the following on the car. cylinder head gasket, timing belt, tension pulley, idler roller and water pump replaced. battery and engine computer replaced. camshaft adjuster and electrovalve have been replaced. the car has had a major overhaul, oil, spark plug, air filters, ignition coil replaced.@@Motorcarnut

Fuel, ignition or low compression related. Start with simple things like spark plugs and gap, ignition coil or wires, check for low compession should be over 90 psi

Now not shaking shaking problem solved but only loosing pickup when ac is on an after heating 120 on 2.5 rmp for crossing speed it starts to misfire only on 2.5-3 rpm

And also smoking black when I full accelerate

Sounds like you have a timing problem and a fuel mixture problem. Make sure fuel pressure is good, start there.

Yep or sticking valves, just diagnosed one recently.

@@Motorcarnut definitely! Did you get to repair the vehicle?

Yes, all done and gone, lol

Not only on 1 cylinder usually it’s a P0300

@@Motorcarnut strange my 2015 Jeep Cherokee had the misfire code p0301 and mechanics said it was a bad evap valve

I mean anything is possible, but the evap system isn't only for 1 cylinder it's for the whole engine.

What vehicle?

Same me

Just did valve cover gasket with spark plug tube seals, changed spark plugs, used multimeter to check ignition coil and injectors, installed new coil boots and spring, cleaned injectors and installed new seals, and I’m still having constant P0306 issues. It’s only that one cylinder. Killin me.

Check cylinder compression

You probably have a vacuum leak somewhere.

Sorry that can be anything. Local mechanic is your best bet.

Can be any engine

If it’s a brand new vehicle bring it back to the dealership? You shouldn’t have to worry about a brand new car? Could be a bad ignition coil or plug or a small vacuum leak.

@@Motorcarnut thank you for the reply! Yes! I went to dealer of my car brand. They are the persons who cleared my issue which i have said above. But, it's a brand new car, so why could it have issues? Any manufacturing mistakes? What I'm thinking is the people in dealership just rised my rpm little bit to cover that exhaust sound. So eventually if rpm is on rise always , engine cannot go on idle , so i cannot hear those sounds. That's what they did to my car. Is these good to do? Or it will cause illness to my car furtherly?

No it’s not good, they are being lazy, artificially raising the idle will cause the car to burn more fuel and the idle is usually computer controlled so maybe it is something else. What year make and model is it? And what is it idling at now? Usually 750 rpm is normal.

@@Motorcarnut Thankyou for your clear understanding. It's 2023 model Tata Tiago(Indian Brand). my Idle RPM is showing 1000, Those technicians don't know what the issue was as i stay in urban area. They just did whatever they knew. Can you please help me to fix these issue. And now while turning off the engine, the exhaust will crackle (tick tick) and then it will turn off.

Here's my clear edit. Is these problem major thing? Do i need to pay attention on these? First i have visited dealership. They first told me that upgrade of software of ECU will clear problem and they did, still issue remains (misfire comes), then again they did something and issues remains same. Finally sound didn't came , then i taught these guys just rised rpm little bit. They have cleaned my spark plugs and others infront of me and then told now sound will not come. But as of now no engine malfunction symbols are displayed in my borad.

Those would do it too

Very unlikely all ignition coils went bad at the same time, same for all spark plugs. However, when one fails the others will follow eventually. It depends if you just wanted the misfire fixed or all at the same time. Comes down to money and it should be your choice.

@@Motorcarnut Thanks for the reply, will follow your channel and see if I can learn a thing or two from your videos 😊

Thank you!

Boy, you sure did get ripped off !! Next time take it to a mechanic like me who will diagnose your vehicle and only change out the spark plug that needs to be replaced . He should have only charged you like $1.87 at the most. Gotta watch those shady mechanics.

Regular maintenance or hair-on-fire last-minute rush to the mechanic? That's your choice. I will take the first choice every time. I just love it when people have a 20 year old car to sell and they proudly tell me their car " only" has 25,000 miles on it. But, they haven't changed anything except the oil and their belts and hoses are stiff as rocks and cracked. I tell them they have so much DAMM DEFERRED MAINTENANCE and Iist off all the cables, hoses, belts, fluids, filters, etc that SHOULD have been replaced due to sheer age. I don't replace one damm spark plug at at a time!!! The time the mechanic takes to test ALL the plugs and only change one is mote when you can just figure ROUTINE MAINTENANCE should just change all the plugs and coil. Change all the hoses ROUTINELY especially since so many parts are plastic and hoses become stiff when constantly exposed to heat. I'm a 66 year old woman who grew up with a fantastic grandfather and dad, who taught me how to care for vehicles. I managed a family Detroit Remanufacturing shop for 15 years. My earliest good paying job at age 12 was to drill Detroit Diesel cages. I love machinery. Machinery talks to you. You can run your hands over the parts and feel the healthy sulppleness and well lubed parts. If you perform planned routine maintenance and listen to your engine and feel the movement of your car you can avoid being broke down. My son , age 50, asked me why I have never been broken down on the road. I told him that that was not true, I was broken down, once. Once was enough. I was in a dress suit, working, taking a short cut through a remote area in Dan Diego County, in heels with no spare shoes in the car. Idiocy. Out of nowhere, broke down, on a dirt road, two men showed up. They made it clear they were not savory. I was 30. They told me, " ... there ain't no point in screaming". My husband , an ex Golden gloves boxer, suddenly pulled up. He knew something must of happened because I hadn't arrived at our meeting place on time. My husband very quickly showed those guys what was going to happen and they literally scrambled to get away. I had recently bought the Cadillac used and had told the manager the car had an ECM issue. Cadillac checked it out and said nothing was wrong. I had told the manager that HE should trade HIS car with me so HE could be broken down on the road instead of me. When he heard from my husband that I could have been raped the guy gave me his car and took mine....it got fixed. I have never been well off, let alone rich, but I pay daily close attention to my vehicle and maintenance is done as a routine. My current vehicle is high maintenance, a 2002 PT Cruiser. The car is from a friend who died. It's been a good car to train teens on the basics.

I made a video about the Kia recall, If your vehicle has less than 120K and 10 years old or newer, they should replace your engine for free.

Yes, but this was only the top 5

True spot on. Loss of power on hills, jerking sporadically. MAF replaced . Now fixed.

@Gmarkx Great!

What?

Absolutely

Yes

If the camshaft was really worn or broken, yes but usually it’s rare. What vehicle is it?

@Motorcarnut 2019 Tahoe. 74k mile. I'm not a car expert so I didn't fully understand the parts/fix they were talking about.

I would get a second opinion, $9000 is insane

@Motorcarnut it's at the dealership. First I thought it was spark plugs and coil but replacing them didn't change anything.

@bbaldboy a good Indy shop is your best bet. Dealership are rip off parts changers

Most of these vehicles I get in are lack of maintenance.

Can be anything, hard to say.

Most likely plugs or coils or bad plug wires

probably from improper installation.

@@Motorcarnut well I think they were platinum and that might be the problem they used iridium in that year of 5.3

But the insulator would be the same on both plugs?

Check for fuel and cylinder compression on that cylinder

I sound like motorcarnut

@@Motorcarnutscoty*

Well not necessarily a weak battery because most engine can run just on the alternator, a weak alternator, yes!

Do a compression test on that cylinder, should be over 120PSI have videos on compession tests if you don't know how to do it.

That’ll do it.

Was it misfire only one cylinder pop up scan? Or what code pop up

@@art-ip4ue cylinder 6 misfire was the code on a 97 gmc 1500 .

Absolutely that can as well. This video was just the top 5 not every cause

Absolutely, I just mentioned the top 5

Would it pop up code p0302 I chanf plug and coil and injector still misfire

@@art-ip4ue I believe u mean if you changed plugs and coil? It depends cause other things besides coil and plugs can still cause a misfire like vacuum leaks, exhaust leaks faulty pcv valve or pcv valve hose, and even worst head gasket failures. Cars with distributor can have them to it the rotor and cap is bad.

Even more than that

For older vehicles, yes.

Sounds like a vacuum leak somewhere. That code is for a random misfire. Is the check engine light flashing as well as being on?

@@Motorcarnut no no check engine

@@Motorcarnutyes, mine is doing just that… I just changed the spark plugs thinking it would solve it and it didn’t. The truck shakes uncontrollably while idling and then when I take off it sounds horrible and barely has power in low rpm. The check engine light is on and will constantly flash… please help.

You have to check 3 things. Ignition system, fuel system and compression on all cylinders. A bad vacuum leak can also cause the random code.

Lol