So the Cobalt is in the shop. While under boost the car would stutter and start to backfire. Sucks that we had to learn about it when we were on our trip to Georgia. I am guessing it has to do with the charging pipe? anyone else have this issue?

 

charge pipping, you'd know. theres no power and you just hear the turbo spool. Sounds like its something else, was it stuttering and backfiring driving slow and normal? or when you floored it?

 

Coilpack/plug issue. Had the same issue..or very similar. As long as the load on the engine was not high (no boost) the engine would run up to max rpms no issue. Soon as the engine loaded (boost), and it was only above 6psi, the engine would stutter and backfire.

 

So of course the car acted perfectly at the dealership and they could not reproduce the stuttering or backfire. I tried with them in it as well. No codes were thrown and they said if it wont throw a code they dont know whats wrong with it. So time for another long trip back to MD from GA on monday. It only happened in 2nd and 5th gear so far right about when it gets between 5-10psi. stutters and then 2-3 backfires. Could it be moisture in the fuel or Bad fuel?

 

Moisture / bad gas will do it alright, so ya...
Stick with top tier gasoline, drop some lucas injector cleaner, and top off with premium and you should be alright