Okay, got a 93 3.4L camaro, bought it bout a month ago and already had to replace the tranny, crank sensor, and ignition control module. Heres my next little ordeal. Every since i got it there has been a miss, sometimes its a lot worse then others. At idle the car idles rough, but not terrible, now if you go down the road and give it full throttle it seems to have good pickup until about 4500 rpm then it breaks up. If you have it about 2000 rpm in a higher gear and give it about 1/4 to 1/2 throttle it really misses. So first off I put a set of wires and plugs on, nothing, next I checked the fuel pressure and that was fine too. I replaced two out of the three coil packs, and checked the third they all seem fine. So finally I ran some fuel injector cleaner through it and it didn't make a difference. Oh yea and one more thing, when it is cold it runs great no misses and idles smooth, but once the car gets up to temperature (which is normal) she starts screwing up. Lemme know what you guys think.

 

Is the check engine lite lit????

 

Nope no ses light

 

O2 sensors perhaps. When it's cold it's in open loop, when it's normal operating temperature it's in closed loop. Open loop does not use input from the O2 sensors, closed loop does. That's all I can think of right now.

 

on the back of the left side of the plenum there is a green recieving unit. there are three wires coming off it. that sends information on how much fuel to air to use. If that is loose or broken it will start guessing on mixtures and try to stall or miss. on my car the clip was broken to as it was driven it would wiggle and my car would buck and stall. that would be worth a shot to check.

 

ok thanks guys i'll check that plug in the back of the motor and if that does no good then i'll check/swap out the o2 sensors

 

Okay, well I checked that green plug which im pretty sure is the map sensor, and I also put 2 new Bosch o2 sensors in, still no better any other ideas?

 

bump