Lack of Power-no codes

[2004pontiacgagt]

I've been having trouble with my 2004 grand am GT for awhile now. Hopefully someone has had a similar problem and can help. The car has a 3.4L with only about 80,000 miles on it. It has a serious lack of power. It is worse when it comes up on temp. The problem is pretty consistant while accelerating. It will cruise along at 65 or 70 ok but won't pull hills very well and has horrible 0-60. The fuel mileage has suffered greatly from what it was before. It also has a slight knock/ping. What i've replaced: New fuel pump and filter, new cat., i've tried injector cleaner, and I replaced the ignition control module and all coil packs with another used setup that came off a car that ran just fine. There are no codes but when we monitored the system on the computer, we noticed three different cylinders misfiring at random times. I don't recall the exact ones but I think it was 1,3,4. I've searched alot of posts and seen many things that might cause the symptoms i'm experiencing (EGR valve, coils, plugs, wires etc.). Any help would be greatly appreciated. Thanks for reading.

 

[planenut_2000]

Try swapping the MAF sensor from another car like it.