Miss firing on multiple cylinders, is what computer test says, changed spark plugs, wires, and a coil cause the middle one (5,2) wasn't firing after all that still miss fire. What else could it be??
The other 2 coil packs. Are the plugs gapped properly? Are the plug wires seated to the coil and spark plugs fully?
plugs not hot enough or not original plugs burning up coils
If one of the coil packs failed, the others may be weak. HTH. -Jim
Looking for a Used Grand Prix in your area?
CarGurus has 2,863 nationwide Grand Prix listings starting at $1,600.
Search Pontiac Grand Prix Questions
Pontiac Grand Prix Experts
Related Models For Sale