91 gtp no power to 3500 rpm

[wyley187]

I am at a complete loss, I have a pontiac grand prix gtp, It is absoulutely horrible on power to 3500 rpm then it kicks in fine, Also while driving at 55 mph it will shake horribly in fifth gear(to the point that I need to downshift to 4th) I will also mention that it has a smell like it is running rich when at an idle, i HAVE CHANGED THE CATYlitic converter, the tps sensor and the fuel filter Please help!!!!!!!!!!!!!!!!!!!!

[bszopi]

RE: 91 gtp no power to 3500 rpm

The shaking at 55 reminds me of when I had a coil pack go bad...

[Rhedalert]

RE: 91 gtp no power to 3500 rpm

My moms old car did the shaking/missing at around 55mph back when the wires started to arc.

[JamesonGT282]

This was found by me on my 300z forum of all places. The question was posted over there so I pointed him to this site :P

[93luminaz34]

I had that exact problem and it ended up that the previous owner had *attempted* to time the car and had the timing off a couple of cogs.

[SappySE107]

Timing will really mess with your powerband. Even if it was in time before, the belt will stretch and your low end will get messed up. The stuttering could be timing if its really off, but I would go for the ignition side since its only in 5th at 55. More load on the motor in 5th gear will show ignition problems real fast. Coil(s) or wire(s). Also check your plugs. I had one crack and it gave me problems under heavy load and fast acceleration at higher RPM.