i have a 3800 series 2 in my monte carlo and it idles smooth and runs perfect untill you accelerate hard and it seems to power surge but if im going 65mph on the interstate and there is a hill or i need to gradually pass someone it actually develops a pretty nasty miss but no engine codes!! i am soooo stumped ive tried several different throttle bodies with good maf and tps sensors it has a new upstream o2 sensor and nothing...ive checked for vacuum leeks and nothing...just did a tune up on it...new plugs wires and i even switched out the ignition module and coil packs with ones that i knew where good and i CANNOT figure it out and its getting old...oh and it will occasionally backfire when i need to pull a hill or pass someone but its not every time.....pleasee help!!

How do the spark plugs look? A misfire is generally bad coils, bad plug wires, or bad plugs. When you pull the plugs look for anything different. They should all be a light gray color. If any are black then you will know where the problem is. Also, have you checked your fuel pressure. Should be about 48 psi.

the plugs look good...but i havent checked the fuel pressure yet. ill have to wait till tomorrow to find that out cause my girlfriend has the car right now lol

moved to it'* proper Mechanical Section. General Chat is for items that affect all platforms and "General Chat". It really helps the GearHeads, others with ownership of same/similar Models, the Forum regarding search bots, and our own internal search engine when we keep things in order. Thanx.