Accleration Problems

[1995gtpGPdohc]

I have a 1995 grand prix gtp. My problem is that when I am acclerating hard from a stop or when I hit about 4000 rpm's my car seems to hesitate or give a little studder and it just doesnt seem like the power is there like it used to be. It does this for anything past 4000 rpm's sometimes, but not always. I also seem to hear a humm when I am acclerating hard with the slight studder. I have a newer serpentene belt on it and I just replaced the A/C compressor (which is the same side of the engine I hear the noise from) but I doubt that could be causing a horsepower loss or studder. The timeing belt isnt in the best condition either and I am planning on replaceing it next weekend. But are there any thoughts on why I could be having that studder around 4000 rpm's? Thanks

[OldSkoolGP]

When I had this exact problem, it was because my coils were shot. Get your hands on another set of coils and see if it gets any better.

[1995gtpGPdohc]

ok, I will check that out