Is the parking brake released? Will the car roll from a stop on a slight hill? Jack up each wheel and try to turn them. The back will be harder in neutral. Checking for a seized caliper or parking brake.

i beleave i found the problem! but im not 100% sure..my knock sensor is broken and need to buy a new one could this be the problem?

I had a shorted knock sensor cable (there are two). The engine light came on but it ran normally.
If you are going to replace a knock sensor (broke off the plastic stalk), get one used from the parts yard, eBay, Craig's list, ect. I believe a 1 1/8" or a 1 1/4" socket fits it. Make sure its not a short in the wiring harness if your knock sensor is undamaged. I ruined 2 taking the starter off different times. Turned out
it was the main fuel pump relay. The engine would not crank when it was hot after stopping and sitting.

well mine is completly broken off but my car runs normal to untill boost kicks in which i heard was ether knock sensor or boost leak..which i have a broken knock sensor maybe a boost leak but none from what i sparyed and heard

ya it rolls even on a slight hill

did you check the engine codes?

a seized caliper has nothing to do with rpms.
i had a caliper seize on me last year and it was only because my system needed to be bled, even still i could drive it while it was seized just after 5 mins of driving it would heat up the brake system and totally stop all movement of the car...

A bad knock signal to the ECU (bad knock sensor or bad wiring) will cause the ECU to operate in what is commonly referred to as "limp mode"... if the faulty signal is interpreted to be beyond a certain threshold... otherwise, the ECU may just pull timing and add fuel causing poor mileage and lack of power but not to a crippling degree.

Fix the knock sensor... it's a MAJOR problem. If you have issues after that post up the details.

Oh, and replace the damned check engine bulb; You're wasting everyone's timing otherwise. The answer could have been right there in front of you (could still be if you have any other issues on top of the broken knock sensor).