mb2

Had the same problem with my gt had to change the battery and the TPS went bad its common when doing any kind of battery or alternater work the TPS goes bad replaced it and shes fine now

JAMAMAN

This is a long stretch, but maybe the spark plug wires are wired wrong. Some D--k head at the dealership did that once to my car by accident.

Never2mucHP

OP: What you describe sounds very much like a vacuum leak. The car should be throwing a CEL; if you can download that it would go a long way to letting you know whats going on.

A good indication is if it's throwing the code for "O2 sensor stuck lean" or something similar it is almost certainly a vacuum problem.

The guy above that stated TPS problem may also be on to something as this would also cause a similar situation.