Thread: NEED HELP!!!2004 Grand Prix GT2 random misfire (shaking during city driving)

can someone. anyone. please help~! ive recently purchased a car on craigslist and the guy told me the only thing the car needed was a tune up because the engine light was on and the car shook when you have it in drive but your not accelerating and when its at stop lights...the car rides fine on the highway and shifts perfect.
ive replaced: a full tune up with ac delco sparks and wires, all the coil packs..and the modulator the coil packs sit on, and the pcv
my mechanic buddy thinks its internal and may be the heads, CAN ANYONE HELP!

Codes?

the first code said something about cylinder 3 misfire then thats when i changed alll the coil packs then it came back random cylinder misfire

can someone. anyone. please help~! ive recently purchased a car on craigslist and the guy told me the only thing the car needed was a tune up because the engine light was on and the car shook when you have it in drive but your not accelerating and when its at stop lights...the car rides fine on the highway and shifts perfect.
ive replaced: a full tune up with ac delco sparks and wires, all the coil packs..and the modulator the coil packs sit on, and the pcv
my mechanic buddy thinks its internal and may be the heads, CAN ANYONE HELP! or may have experienced this problem

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I don't see how the heads could cause that problem. Try checking your positive and negative battery cables for corrosion or shorts (I had a similar issue cable was wedge against engine block and had melted and fused together) Next I would shoot for a short in the ignition system somewhere. Run the codes again and let us know what ya got You said the FIRST code, OK what were the others?