service engine light

this is my 3rd post about this problem. I have a 1997 Grand Am GT, 3.1 L V6. I have given my mechanics the messages I received, however they still feel it is not my wires or coils because he said he put new ones on & it didn't make a difference. Yet the original coils & wires are still on my car. All the injectors were replaced. The engine light only comes on when the car is idle and the idle is rough also, the code that it gives is random misfire. they have changed these injectors more than once this has been going on for months now. The light will also go out on it's own. I have trouble starting it only when it has sat about an hour, in the moring when it is cold it starts fine and when I leave it for 10 or 15 minutes. Also the trouble with the starting started only after they changed the injectors. They don't it is the wires or plugs because it is not a problem all the time. Is there anyone out there that can help please?

ok so the mechanic told you he replaced the wires and coils and you say the originals are still on there? If the originals are still there i would replace those. He said its not the plugs but i would definitly replace those too..especially cuz this guy sounds like hes full of shit. Does it only idle rough while in park or does it do it while just plain idling, even in gear? Checking the air filter couldnt hurt either.

There is a high probability it is the spark plug wires. Overtime the spark plug wires deteriorate or it might be rubbing off against the engine block and causing mis-fires.

Crankshaft Position Sensor wires rubbing off the engine block will also produce mis-fir because the signal of the crankshaft position sensor is the reference signal used by the Ignition Control Module (ICM).

The ICM itself may be failing which needs replacement. The ICM is expensive as well as coil packs. You might be better off going to the junkyard and get an ICM/coil packs intact. Don't forget to use a thermal trasfer grease between the back of the ICM to the heatsink. The thermal transfer grease is different from a di-electric grease used for bulbs or spark plug connections.

definitly could be the plug wires, though im not really familiar with the layout of a '97 3.1L engine

ok so the mechanic told you he replaced the wires and coils and you say the originals are still on there? If the originals are still there i would replace those. He said its not the plugs but i would definitly replace those too..especially cuz this guy sounds like hes full of shit. Does it only idle rough while in park or does it do it while just plain idling, even in gear? Checking the air filter couldnt hurt either.

Thanks, We did replace the air filter and the car idles rough only when it is idling and that is when the light comes on. (in park)