I have a 1995 Lumina. It idles nice. You can rev it in neutral up to about 3500rpm then it stubles - almost like it is hitting a rev limiter - not the problem, just a symtom. When you go to drive it, when you initially step on the gas it will stumble and buck BADLY, sometimes it will 'catch' and will go like a bat out of you know where. I had the fuel pump and filter replaced, and the fuel pressure all looks good and I just did a tune up, wires and plugs. The coil packs ohm out ok, there are no codes to speak of. I have an actron CP9185 scan tool to check the codes and see live data. The tool says that I have a bad 'Quad driver 4' - but some have said that the toolwill say this in error? I am leaning toward something in the transmission, but I'm not sure. I really don't know what to do with this car and any help would be appreciated.

 

I've seen a cracked coil pack and plug wire grounding out on the engine cause a stumble like this.........Tom

 

ended up being a bad coil pack. thanks for the reply