I have a 1999 3.8l camaro with random mifire code being displayed. I have replace coil packs,plug wires,new iridium plugs,ignition control module. I still have the problem so i changed fuel filter,removed catalytic converter,checked fuel pressure its at 45psi. Still have same problem it also when coming to stop volt gauge drops then goes back to normal had charging system checked and its fine. Checked for vacum leak dont have one, MAF sensor is working fine and so is egr valve. Does anyone have a idea

 

The only thing you didn't mention is your fuel injectors. You should be able to tell if one is causing a rich or lean condition by looking at the plugs. I've had a random misfire before, and the injectors were one of the last things I looked at. I actually found which cylinder had the misfire by the black sooty spark plug (running rich). Pulled the injector out and soaked it in carb cleaner, and it works fine now. As an easier fix, you can try putting some injector cleaner in your gas tank for a couple few fill upsto see if it clears up. If it isn't a mechanical issue with an injector, it could be electrical, which you can check with a meter at the injector.

 

I have tried that and still nothing. Today i unpluged map sensor while running engine shut off, pluged back in now it wont start?

 

I have the same problem. However, the motor seems to be off on timing. Could a timing problem set off the random misfire code?

 

Timing is controlled by the computer, no moving parts. However the PCM in your car has to get a signal from the Crank Position Sensor (CPS) in order to know when to fire the plugs. No, or bad signal and engine won't start.