when i first purchased my car, it was misfiring horribly. Then i changed the spark plugs, and the wires and that made a big difference. It still would misfire sometimes but not as bad as before. Then i installed new coils and that helped too. but it still tends to misfire occasionally, could the ignition module be going out????

Not likely.

Diagnostic code(s) would point us in the right direction. Your local auto parts supplier can scan it, but they tend to be less than reliable. A GM dealer, or any competent shop would be a better choice.

Meanwhile, we can work with what you do know:

You have a misfire. How often? At what speed? Is it always the same cylinder, or is it random?
Does it occur under load? Cruise? Decelerating?
When it is cold? Operating temperature?
How often have you filled the gas tank?

Norm

it occasionally misfires when it shifts into overdrive, but it doesn't keep doin it, it will do it for like 5 seconds then it will stop, it won't do it at all untill it gets hot, i'm not sure what cylinder misfires but i will take it to a gm dealer asap.

Try throwing some water on your ignition module while the car is running. If it cuts off, that's your problem.

Check for a plug wire (#5 or 6) touching the O2 sensor or its wire. Pull all the plugs. Does one look any different than the rest?

Is the coolant at its proper level?

Norm