2004 grand am GT lack of power

[2004pontiacgagt]

I have a 2004 Grand Am GT with a 3.4L. Awhile back I had a problem with the car not downshifting when the cruise control was on. It would bog out in overdrive on big hills, often times the speed would drop down from 60 MPH to under 50MPH at which point the cruise would shut off. After driving manually for a few miles the cruise would come back on by itself. This was a bit of a pain but not a major problem, we continued to drive the car as it was. Now the problem has changed (assuming the two have something to do with each other). The cruise works fine now but I've noticed a serious lack of power. It doesn't really miss like an electrical (spark) problem, more like it just doesn't have the power. When this problem first surfaced it was only part of the time. When this would happen, if I would let off the gas completely then ease back into it, it would come out of it. The problem has gotten worse and now does it most of the time. I've had to downshift on level ground to keep at 60MPH. We have replaced both the fuel pump and the cat. converter, neither of which helped. The service engine light isn't on, however it did flash about 8 times on one occasion and then shut off. We put the scanner on it and no codes came up. Any ideas? Thanks for the help.

 

[melsg5]

When you replaced the pump, did you change the fuel filter? have you checked the fuel pressure at the engine?

 

[2004pontiacgagt]

Re:

We had replaced the fuel filter not very long before replacing the pump, hoping that was the problem. No we haven't done a fuel pressure test, might be a good idea though to rule some things out.