So I have an 04 cavi and it has an aem intake, hi flow cat, and 2.25" exhaust.

As I drive down the road on the interstate and everything is fine. If I go through town to say, my house, and press in the clutch to shift to a different gear the car sputters for lack of a better word. It is almost like when i go to re-apply the gas after shifting the TPS is reading slowly and the computer doesn't give gas and suddenly is like it tries to make up for it then it evens out and all is fine. til the next time i shift. after i say, drop it from fifth to fourth and take it to about 4-4500, it is fine. for a few days. it has been getting worse since about december. I'm thinking possibly TPS mis reading. i'm doubing an 02 sensor problem. seems more random then that. I am not too sure anymore. The dealer said it was because of the way i was shifting and said "don't shift like that anymore" any imput would be much appreciated.

I forget the technical service number, but this is a known problem. I also have an '04 cavalier w/ manual transmission, same exact problem. Also, it does seem to get worse in cold weather. It all relates to an improperly programmed ecu, and as I said there is a TSB, but not a recall on this.

The fix is to get your car reflashed by a GM Tec-II tool (dealer item only), which can cost up to $100. If that seems like a waste to you, you can try and ignore it. The problem doesn't represent any broken parts (your TPS and 02 sensor are most probably fine) and does no damage. Its just annoying. Do a search for "ecotec sputter" or some such thing, and you can read all about it.