There could be several possible causes for a 1990's Ford pickup truck to idle with erratic RPMs. ⬇️ Here are a few possibilities: 1. Vacuum leaks: A vacuum leak can occur when there is an air leak in the engine's intake manifold or hoses. This can cause the engine to idle irregularly. 2. Faulty idle control valve: The idle control valve controls the engine's idle speed. A faulty or dirty idle control valve can cause the engine to idle erratically. 3. Dirty or clogged air filter: A dirty or clogged air filter can restrict airflow to the engine, causing it to idle irregularly. 4. Malfunctioning throttle position sensor: The throttle position sensor monitors the position of the throttle and sends signals to the engine control module. A malfunctioning sensor can cause the engine to idle irregularly. 5. Faulty fuel injectors: Fuel injectors spray fuel into the engine's combustion chamber. If a fuel injector is faulty or clogged, it can cause the engine to idle irregularly. 6. Malfunctioning EGR valve: The EGR valve recirculates exhaust gases back into the engine to reduce emissions. A malfunctioning EGR valve can cause the engine to idle irregularly. ♦️ One time I took the EGR valve off of an engine, I replaced it with a new EGR valve to no avail. So after that I took off the EGR valve and I put a flat metal plate over the hole and reinstalled the EGR valve. After that it was completely fixed. To this day I still cannot figure what happened there! 7. Then there are the PCM and the ECM. Us older people refer to those as the computer or the brain. The fundamental distinction between the two is that the ECM regulates and sends orders to particular areas of the engine. In recent models, the PCM controls practically all engine functions. However, there is a narrow line that separates the two. Most people, even automotive professionals, mistake the two. The ECM and PCM govern engine operations that must work together to burn fuel effectively. When the engine stumbles, coughs, or stalls, it may be due to the PCM or ECM failing to regulate the fuel mixture or the firing of ignition components 8. Then last but not least is the electrical system. It could be faulty wiring anywhere on the engine that runs to any controlling component of the engine. ♦️🩺🔧🪛⛑️ My mechanics instructor when I went to vocational School once said: "Being a mechanic is just like being a doctor. You must be able to diagnose the problem before it can be fixed ❗" 🔨⚒️🛠️ If I have ever heard a true impacting statement that was it ❗ It's important to have a qualified mechanic diagnose the issue to determine the exact cause and recommend the appropriate repair. 🥺 After all, they've got the fancy computers and electrical equipment that we just don't have........
Thank you papaw, my wife's truck that she loves was saved because of this video. We have been chasing this problem for a long time and the ICM was our problem!
I installed a 1990 4.9 into my 79 f150, converted the intake to a carb and set a 54 one barrel carb on it and set a point distributor in it, runs like a haint. Installed a 5 speed hydraulic slave trans in it from the 90 f150. cut and redid the pedal to push the slave. pro job.
I've done similar things. I pulled a 235 six cylinder out of 68 GMC and replaced with a 350 v-8 Malibu, pulled out a 3speed and replaced with a Vega fully synchronize 3 speed, shorten the clutch rod took two transmission splines to make one, U Joints was two different types with retaining clips on inside on one end and retaining clips on outside on the other end. ☺️ It all worked out.... 👍
Sorry I haven't responded to some of your questions. For some reason I'm not getting any notification about responses to my videos and I'm seeing so many from months ago I figured it was too late to get back with you guys. Again sorry about that.
Seen this video before if you have a hard start rough idle and chuggy acceleration or break up like your running out of fuel it could be the vacuum can (aka coffee can) other fender well i changed everything wire harness computers injectors fuel system even a full engine rebuild and truck ran same as when it all started 2 yes ago and found I had a huge n very quiet vacuum leak I putt a plastic round vacume ball on and this 300 is has some serious power now its all fresh n correct so jst saying for anyone having trouble and can't figure it out after replacing expensive sensors check that can mine had Swiss cheese out rite under the mounting part couldn't see it now im 8000 in under hood after missing this but its pretty everything got painted while apart
I forgot about this. I have a 1991 f150 that I mastered and it runs great. But I bought same exact 4.9 manual trans. was running awesome but after emissions test it started running really bad. Barely can make it to 60-65 mph and will stall when I get off freeway. Replaced all sensors except for ICM, and haven't replaced vacuum canister
🤔 Here's another thought: Many people, including professionals, get confused by all the acronyms used in automobile mechanics. A PCM or powertrain control module is different from an ECM or engine or electronic control module, even though most people believe the two are the same. Most modern or newer models only have a PCM, which controls all the engine functions, where the ECM only controlled certain parts of the engine. ECM Some of older automobile models had two computers, the ECM and the TCM. The ECM controlled the engine function, but the transmission was controlled by a different computer system called the transmission control module, or TCM. The ECM was also used with vehicles that operated with a manual transmission because there was no need for a computer to operate the transmission functions. PCM The PCM is the main computer in the automobile that controls all the functions of the vehicle. Everything from the vehicle's timing to the proper flow of fuel into the fuel injection system is under the control of the PCM. Along with the engine functions, the PCM controls the functions of the automatic transmission, such as automatic shifting when vehicle is accelerated or downshifting when the vehicle slows down. The PCM does not have as much control of a manual transmission. 🔧 🩺 I hope this clarifies the situation a little about the old term "COMPUTERS" LOL.... 😀 🤖 💻
This device is my last component to replace. On mine it's on the distributor. It runs so crappy apon start up. Once it's good and hot it runs close to perfect
What is the correct part number for an ignition control module for a 1995 4.9l f150? Because they always sell the wrong part number and the people at the store don’t really know either
I'm having a very similar issue with my 78 mustang tachometer is all over the place misfires when cold seems to get better once it's warmed up but something definitely isn't right and I can't figure out what it is!
I'm not a expert, but check the following: the distributor bushings, EGR valve, there are so many things that can cause it. Get someone to hook up a good diagnostic computer and they will probably figure it out. Also, some vacuum lines are thermostat controlled, when the engine is cold the vacuum lines are not sucking any air but when the thermostat warms up on certain vacuum lines if there is a leak then you will have an engine misfire. Like I said, there are so many variables, find a good mechanic that has a good diagnostic computer and they more than likely will find your problem.
Kind sir would you be willing to film or sending me a message showing how your vacuum lines and EGR lines are connected? My truck has been worked on and I'm not sure the lines are connected correctly and I can't seem to find that information anywhere. I would very much appreciate it!!!
@@heroooo9684 I replaced all my vacuum lines, I have diagrams but you'll probably need to PM me somehow. I found my hesitation problem was because my EGR valve would open too much and the truck runs lean. I ended up cutting a restriction plate and drill 2 ⅛" holes to limit the amount of gases recirculating my system and it improved a lot! Now I know if the truck starts "chugging" again I just step on the throttle and the problem goes away. I found this out by switching the vacuum lines on the canister, I ended up with a Check Engine Light but the truck ran perfectly. I found the EGR starts opening up when the engine temperature reaches 150 degrees F. Hope this helps!
Hi, I have a 4.9L straight 6 and my truck vibrates and makes a creeky sound occasionally but not all time also sounds like air flow is louder, like shoooooo air, if you know what I mean, Vern. What do you think it could be? Any suggestion is appreciated and your truck sounds like a solid horse.
It could be many things, you could have an air leak, the vibration could be a broke motor mount and if you're driving it down the road it could be a worn out universal joint. The creaky sound could be worn shocks or bushings. There are so many variables.
Could be a week coil or a bad distributor cap or even a bad distributor. My distributor went bad on this truck and found the brass bushings on the distributor were bad and it caused the truck to quit intermittently. It was as of the key was turned off.
@@changingtimes37766 I changed everything to do with this problem. Just changed the distributor out and got it back in time today. Time will tell if this fixes my stalling problem. Next thing on the list is MAF and Throttle body. It still has a small miss and tack fluctuating sometimes. I've been chasing this problem for months.
Mine idles from 500 to around 1200 rpm. Did it fix your issue. I replaced egr valve. Purge valve. Throttle position sensor and idle control valve. And no luck. Mine is also a 5.0
I dont have a tach. I think the previous owner put in a junkyard dash/display. Is it suppose to have a tach? I also deleted the smog system. Maybe that's the issue. I've been told egr delete wont make it run bad, it just puts exhaust into the intake. I'm still hunting down issues with mine.
If you don't block off the EGR it will suck air into the system and cause your vehicle to run very bad. You can take your EGR off and put a flat tin or metal plate over the hole and then reinstall the EGR that will effectively block off the EGR. You can also buy a over the counter tachometer.
There are so many things that could be causing the problem. Get someone to read the code and it may give you an answer. The distributor bushings were bad for wearing out on the 1995's also. A code reader may be the best way to diagnose it.
Got something funny to tell you put all new parts ICM and top of the line coil pack Accel on my 4.9 would not crank put the old Parts back on it and it cranked and ran now after it warms up it starts running rough go figure anybody can help thanks
Get a code scanner made for your vehicle. Or take it to a good mechanic and let him read the code. It sounds like a wiring issue or it could be an air leak somewhere. Even on the automatic transmissions there is a wiring that can affect the performance and running abilities. Without a code reader it may be impossible to find the problem.
They're really not that expensive. It depends on your truck make and model. It's called "Electronic Ignition Control Module". Don't call it "" ENGINE". * ( The parts store will think you're talking about the computer.) Call it "IGNITION module", it controls the fire to the coil and or distributor, and evidently has an effect on other things such as the tachometer.
ECM engine control module. The PCM is Power train Control Module this is the computer more or less. The ECM is not the same thing. The PCM is found on the firewall the ECM is found on the fender. *Also I worn out bushing on the distributor can cause similar problems, but you would need a good mechanic with a good computer to find that out.
