OK here's one to throw out for some ideas. My engine seems to have developed a strange but very repeatable misfire. Particularly when it's cold but sometimes even after it's warmed up, I've got one cylinder missing completely at idle. Light throttle, low revs, I'm running on 3 cylinders. Seems like around 3500 RPM it smooths out and all 4 cylinders pick up, similarly when the engine warms up and I get on the highway it smooths out (although I've felt it drop back to 3 cyl on the highway for a second or two).

I checked this at idle by pulling plug wires and observing - removing the #2 plug wire had absolutely no effect on the engine idle, while 1,3,4 all just about stalled the engine. So I'm almost positive I'm either getting no spark or no fuel in #2 - but what's strange to me is that it comes back at higher revs. Even at idle if I put the plug wire near the valve cover I can hear it sparking so I know the distributor / wire are getting spark there. Is it possible that I've got a really badly fouled plug that only clears at higher cylinder temps or something? Anyone had anything like this? I'm going to pick up a new set of plugs today one way or another, and if that doesn't help I'm going to start checking for a plugged injector or something.

 

If its popping and back firing then it's probably fouling the plug . if it just looses power and misses then it mighy be your injecter check for water in the injecter connecter or any where else for that matter. I've had some interesting moments of trouble shooting at 2:00am at the local self wash after degreasing my motor . check your cap & rotor to.

 

I have been fighting my car sence last week with all kinds of problems ( took off the suprercharger to smog her ) . same thing # 2 . I changed injecter , distributer , plug wires plugs last night . I'm changing the cap & roter and resister box tonight . I tried two diferent computer boxes to , same thing . it seems to be low rpm high load . if i lightly crack the throttle it's fine . when I mash it it misses . I am going to try changing the tps , & map to . I'm going to put the AEM race box on soon so if I dont find the problem I will probably start taring out the wireing and going over it with a fine tooth comb . let me know what your solution is .

 

Ok here goes .... new cap & rotor same thing . new injecter resister same thing . checked tps proper voltage .032 volts closed 4.90 volts open . Then i found my ajustable fuel pressure reg that i built 8 years ago was leaking out the vaccume tube sucking raw fuel down cyl # 2 . ah ha I thought i had solved it by changing that out .... nope . It pops and sputters up to 3000 rpm then smooths out . sence all my wireing runs through the firewall on 2 cannon conectors I think i will try pulling that apart . Its got to be somthing stooped . Let me know your progress

 

Ok I think its your O2 sensor . if it is bad it would pop and miss until it got kicked out of open loop at 3500 rpm . I'm changing mine tonight . I'll let you know . if you are still checking this . if not I'm just posting for my health .

 

Crap, I'm checking this, because I only get 2 cylinders, and then 3, and then finally 4 when I start my car some mornings........This is the first time it's been cold after I've had the turbo on for a while, so I don't know what it could be.

I've had a check engine light on for a while about some ignition problem that the locals said would cost $600 to fix, but it wasn't causing any problems for the longest time. I have stock ignition and am thinking of upgrading. I also have stock fuel injectors, and 1 range colder plugs. When someone suggested fouled plugs, I took it on the highway and did a few full-throttle 50-100 runs in 5th gear, maybe to heat up the plugs a little more, and it seems to start better now, but I'm still not sure. Any suggestions?

Thanks,
Nick