hey all! i have a 2002 bonneville with an issue that i am trying to take care of without being "raped" by a repair shop. my car feels like it has a rough idle and sometimes it seems like it wants to die. hasnt yet but that is what i want to avoid. i took it to autozone and had them do their lil free diagnostic on it,and got conflicting answers. so i changed the plugs myself and the wires. still doing the same thing. i took it back and had them do it another test. first test said emission sensor the first time, after i changed the plugs it said multiple misfires. so i'm not trusting in what they say. only other thing i notice is if i am driving high speeds or going into overdrive i do notice what feels like a "miss" in the motor. can anyone help shed some light? i am in the texas area

Sounds like a coil issue. You sound like you have a little skill in working on the car. So that'* a good start. here is a write up on testing the coils.

https://www.gmforum.com/t278818/

Another thing you can try is take a spray bottle with water and mist the coils, wires, and plugs while the engine is running. Then turn off all the lights so it'* real dark. Watch for blue flashing. If you see that, you have a ground short. Make note of where you see it and let use know.