My girlfriend has a 2001 grand Prix with I think the 3.4 I cant remeber and I am in Iraq so I cant check. Anyway the car has barley any power. You have to ease into the gas to get the car to start moving and it takes awhile to get going. I put a scanner on it and the only code it reads is for an o2 sensor bank one bad so I replaced it and the other o2 sensor. The car stills acts the same and still kicks a code for the o2 sensor. I am thinking clogged cat but not sure anyone have any ideas? The car has 120k on it. thanks