Engine stalling while idling. Rough idle

[Rehashed]

Hey guys, I have a 1992 MM 2.4L 5speed 2wd. I've been having an issue where I can start my truck right up and it will idle pretty rough and has a cough. it will idle for around 15-20 mins and then it will stall out. It will also stall if i rev the engine and let it drop to idle or if i turn my steering wheel sometimes. I do not have a CEL. I was having an electrical issue and replaced the alternator and reground the engine so I believe power is not the issue. I did a tune up, replaced the fuel filter, cleaned the air cleaner assembly and throttle body. After it stalls sometimes it will fire up again but eventually it will crank but not start. I can come back out the next day and start it and it will fire right up. Has anyone had any issues similar or have an idea of what to check next? Thank you

[finalfighter]

check the ecm for burn components. next thing would be to make sure the MAF is good. only way to check it is by having a known good one available. you can get the clone/copy ones on ebay for cheap. id bet you its an ecm problem tho. post up a pick of the insides.

[finalfighter]

you can use this MAF on your 1992.

https://www.ebay.com/itm/Mass-Air-Fl...fyd1f&LH_BIN=1

just be sure and change the plastic plate on the front. if you dont it wont run right.

[Rehashed]

I will try to take a picture after work. I was fearing it would be ECM but I did flash codes and it is saying nothing is wrong. Can the ecm be shot and flash codes still say everything is okay?

[Rehashed]

I was thinking map sensor and bought cleaner only to realize you can not clean it without damaging it. I was thinking it would show on the flash codes or a CEL if the map sensor was bad but maybe not.

[Rehashed]

I meant MAF in previous post

[camoit]

Check the timing when cold and then as it’s having a problem. My bet it coil.
as the coil changes so will the timing.

[Rehashed]

The ignition coil? That might make sense because the cough and rough idle it has is not random. Its running smooth then rough idle/cough then smoothen rough etc. Then after a while it will stall out. Then sometimes not start back up until a bit later. I might have a few things going wrong to be honest.

[Rehashed]

[Rehashed]

So looks like the ecm is already replaced remanufactured. How does it look? I also ordered an MAF. The truck has 79k miles i cant see it needing a 3rd ecm but who knows...

[Rehashed]

Thank you it ended up being the coil!

[Rehashed]

Hello, so i am still having an issue with the truck stalling at low speed or idle. I replaced the coil, distributor, alternator, fuel filter, starter and i also tried a reman ecu. My issue is that the engine runs rough at idle and will stall either at idle or at a low speed. I can start it right back up usually but sometimes it may take 2-3 key full turns to start. Sometimes the key turn sounds like its about to turn and then will not and thern i can try again and it will fire up. Nothing so far has solved the issue. Im thinking either the reman ecu i got was defective, the fuel pump is bad or something electrical. Im really going crazy trying to figure this out. Any thoughts?

[tortron]

Humour me and spray some carb cleaner around all the gaskets and vac lines.

sounds like it could be a vaccuum leak. so either a gasket in the intake side, or a vac line is split.

You are listening to the engine speed, if it climbs up then that area is leaking

[tortron]

oh and the hard starting sounds like the timing is out a bit. possibly been altered to make up for the potential vac leak.

[Rehashed]

So its not a rough start it just sometimes wants to start and then wont turn over. Next key turn it will fire right up no problem and then sometimes idle for 10-15 mins sometimes shut right off. Im really leaning towards a bad IAC valve. When im at speed it never stalls and runs smooths until i come to an idle or low speed. The tac will jump a bit and then low rpm and then stall. I also noticed when the battery is disconnected for a while and then truck is started again it runs prefect until the ecu runs into whatever the issue is. I will try the carb spray for vac leaks but it doesnt seem like that kind of rough idle or stall. Its a more consistent rough idle/ low rpm and exact shutoff.

[xboxrox]

Replace the ignition switch !!
You're Welcome

[tortron]

Oh yup. so when you crank it the starter will try turn the engine over but stops.
Thats timing.

can you confirm what you set the timing to?
and did you do the method to put the ecu into the mode to change the timing? (you use a jumper to set it, theres some other info on the site)
you can test the air idle control valve with a mualtimeter, you measure the ohms of it, info in the manual. easy to test that rather than chase a problem with new parts


Do you have a timing light? ou could confirm the timing when it starts up and then if it changes when it dies

[Rehashed]

So tonight i cleaned the throttle body again and started it up and took it for a ride and drove about 2 miles. Engine must have gotten up to temperature. While driving it bogged out and the tach dropped and then shot back up. Kept going and then it bogged again and stalled. I pulled it off and tried to start it up multiple times and it will not start up. I bet tomorrow when I go back it will fire right up as this has been the case before. I’ll let you know. I am going to take it to a shop and check the compression just to make sure it’s not a shot engine. I will also check timing and whatever else I can think of. I’m thinking maybe the reman ecu I got and installed may have been a dud. Maybe need to send out my current ecu and see if someone reputable can repair it. I’ve fallen in love with this truck but it honestly is only giving me issues since I’ve had it.

[tortron]

Maybe. Sounds a bit like the coil is a dud too. Cutting off like that when warm but fine when cold.

[SubGothius]

That bit about the tach just dropping and coming back does seem coil related, since the tach is driven off the same signal that fires the coil. Maybe the ICM, if that's still separate from the ECU on FI models?

[Rehashed]

So the truck had a newer coil in it that I just replaced with a brand new ngk coil that was in a sealed bag. I did order a icm a day ago because I was reading they are a part that fails when at temp and it was cheap. I’m thinking I could have multiple issues. Possibly incorrect timing and then something that is killing spark or possible fuel.

[xboxrox]

I am too ignorant to try testing all the parts you have Rehashed but YouTube Scotty Kilmer is sometimes helpful for me & although your truck is not 40 years old yet, I still suggest [that if all else fails]
replace the ignition switch & does your truck have fusible links circuit breakers between the battery & main wiring harness (?) If so, maybe they have loose connections or need replacing..?

Most Respectfully & Good Luck
George

[SubGothius]

When installing the new ICM, make sure to apply thermal paste between it and the plate it mounts to. Should come with a little packet of it, but if not, you can get some from auto parts or computer/electronic parts stores. Autozone stocks it, part #SL203, or Home Depot offers Super-Lube #98003.

[Rehashed]

Awesome thanks for the tips. Since I’ve been having these issues I have binge watched Scotty Kilmer. He is great I even was thinking about contacting him if I can eliminate a few more cheap fixes. I’ll let you know how the icm goes and any other updates.

[tortron]

when it dies pull the plugs and smell for fuel, if its losing spark they will probably be a little wet