No power in 4500+ RPM Range

[darkgh0st]

Car is a 2001 Grand Prix GT 46,000 miles. I plan on hooking into the PCM soon but haven't yet. The problem is in the high RPM band. Accelorates great until it hits the 4500RPM and then just hesitates. At WOT it will make its way to the redline and just stay there at the rev. limiter until I take my foot off the gas. The Low coolent light will come on for a few seconds and then go out again (coolant level is fine). I have a k&N that was recently cleaned, and just changed the fuel filter. I'm concerned that I might have phucked up the PCM with my K&N mod since its now exposed without its stock airbox to live in.

Any ideas??? This is driving me crazy

[99_gtp]

check your plugs and wires and all connections to them are you pulling any codes from the computer

[darkgh0st]

Havent plugged in yet to check codes. Would codes show up even if the service engine light isn't on?

[lakerfan1784]

Codes will show up on the scanner if the SES light has come on. The computer stores the codes, and the scanner reads and displays them. If the light has ever come on, there will be a code, unless you have recently disconnected the battery

[Ripn12s]

So the car is not shifting at WOT in "D" ??

[darkgh0st]

The SES light finally came on over the weekend. I will plug in soon to find out whats going on with it. Thanks for the suggestions so far