I have a 02 Grand Prix GT with non-supercharged 3.8. Car has 96,000 on it and I notice that it hesitates going up a hill under a load. It "coughs" going up the hill and it is fine, usually when it trys to downshift. I tried putting fuel injector cleaner and replaced the fuel filter and it still does it. The dealer put it on the computer and there were no codes that came up regarding this problem. Transmission seems to be fine too.
Has anyone had this problem?? I'm trying to pinpoint the problem whether it is the transmission or maybe anything fuel related.
Thank You