2004 grand am gt lack of power

[2004pontiacgagt]

I've got a 2004 grand am GT with the 3.4L in it. It only has around 70,000 miles on it and it has a serious lack of power. Driving around town at low speeds it runs fine but when you get out on the highway and get up around 50 it is gutless. I've put a new fuel pump and fuel filter on it, new cats, and replaced one coil pack that didn't seem to have as hot of a spark as the rest. After the coil pack it seemed to run better for a day or two, according to my wife. After a couple of days, I drove it and didn't notice a difference. There is no service engine light on. However, on two different occasions I really stepped into it while it was stalling out and the light flashed about ten times. My owners manual says it does that to indicate a miss-fire. I pulled three of the spark plugs (two on front and one on back) and they all seem fine. Any suggestions? Thanks for your help.

 

[melsg5]

Have you tried a fuel pressure test? When the light comes on can you get the code checked. A number of auto parts stores such as Autozone do it at no charge.

 

[white98bonn]

i'd try diagnosing the ignition system. ignition control module maybe?

 

[2004pontiacgagt]

No we haven't done a fuel pressure test. Do you know what the pressure is supposed to run? We tried to pull the codes but didn't show any. The owners manual says when it flashes it is a misfire code. How can you diagnose the ignition system/ignition control module? Thanks for the input.