1993 3.1 Lumina idles, misfires, mystery stalls

[szczur]

Hey guys, new to the forum.

 

I'm having a car problem that's stumping everybody I've asked. They say it could be all these different sensors or the fuel regulator and/or pump. My 1993 Lumina up and stalled out with no warning one day, and since then it has not run right. It will start up and idle roughly forever, but when you hit the gas it will lurch/rev up and down, misfire variably, and then stall. The length of time it will run before stalling varies but no more than 5 minutes. Check Engine light is not on, was checked to be working, no codes. Recently ran idle relearn, replaced MAP and IAT Sensors. Am going to check fuel pressure. Any ideas?

[GTP091]

Bad Coil would be my guess. Pull the spark boots one at a time and listen for a change in idle if you can get it to idle. If there is not a change in RPM then that plug is not getting spark. if it's a coil, 2 of the plugs will show it and means your running on 4 cylinders

 

check your timing belt...

Edited April 13, 2011 by GTP091

[biddieboi]

i second that. I would also check my spark plug wires because i had one bad wire an it caused misfiring and stored trouble codes in the computer. Do prelimary checks for all electrical work.

[Myotis1134]

I am having nearly the same problem, and I have replaced all my ignition-related sensors, spark-plugs and spark-plug wires, and most recently coils. The rough idle might be from a bad coil, but it more probably will turn out to be a bad ignition control module. Those seem to go out often on my car (91 lumina euro 3.1). Check out my post (Something Not Right Here) and see if the symptoms match up. I would get mystery stalls, which grew increasingly worse. The car will not start now, even with all the crap I''ve replaced, and I picked up the new ICM a bit ago. Going to replace it tonight and see if it fixes the problem.

 

Have you checked to see if you are getting spark yet? I really wish I had done that right off the bat, then I wouldn't have replaced so much crap that probably didn't need it.

[szczur]

I checked fuel pressure, and it was at 15 psi. Apparently such low pressure does cause misfire (according to the gm manual), and there isn't a sensor for it on the vehicle! Replaced fuel pump and fuel filter this weekend, and it has not stalled so far. Also I cleaned the IAC sensor: there was actually a thick cake of black stuff all over it, (19 years of dirt, doubt it was ever changed) to help stabilize the idle. Still idles/runs pretty rough though, I probably should make sure those spark plugs aren't kicking the bucket.

 

Hope this helps anyone with a similar problem!