V1c here again. I got a 95 Camaro 3.4L auto and I've been having this problem with the car after it getting to its peak running temp it starts to backfire upon accelerating. Idels kinda rough too...

This does not happen when its cold or cool...It runs like a champ when its cool and fresh from the crank.

I just got my Cat replaced with a Magnaflow highflow and that made some difference as to how servere the problem was before I got it fixed. The mechanic said to drive 40-50 miles around on it and if I get any lights to come back. I've been looking around and from what I've read from others on the forums with similar promblems, I think it could be the mass airflow sensor.

Also, could anyone tell me what the cable next to the throttle cable is for? Its to the right of it if your standing in front the car looking at it...

 

Maybe it's related to the PCV or Oxygen sensors? I have a similar problem on my 3.4L -- I am just about to replace the plugs & wires, since they're about 5yrs old... We'll see if that helps...

For your other question, get a Chiltons or Haynes manual...

 

The car seems to act up when it goes into closed loop. This means a sensor is probably bad. Look for any active and retained codes, as they will give you a starting point. The PCM in this car will detect a dead sensor, but is not sophisticated enough to detect a malfunctioning one. Using a scan tool, not a code reader,you can look at the output of the sensors and see if it makes sense. If the output is out of line, the sensor is bad. Ex. ECT sensor indicating a coolant temp of 200 deg on a cold engine. The car will run without the MAF and revert to the MAP for engine management, so you can pull the wires off the MAF & see if the car runs better. The problem with this test is that the PCM gets forced into open loop, and ignores most sensors. If the car runs OK with the MAF disconnected it proves you have a sensor problem. However, it could be the MAF or some other sensor. With a scan tool you can look at the O2 sensor output, and verify that the output is constantly changing at a rapid rate, if the output is steady, the sensor is bad. You may also want to check the ignition control module under the coil pack, as they can act up when hot. The extra cable is probably from the cruise control.

 

Pete, you're truely amazing. My whole time owning a camaro you've been around to help.

 

Ok, with the MAF sensor off or no, it runs the same. So...MAF sensor... Gunna call the shop that did my Cat and ask them what they think.