Does it still idle smooth? or is it a bit erratic? Sounds like excess exhaust backpressure or a TPS problem (which may not throw a code.)

If it idles a bit high, then start looking for vaccum leaks. No vaccum= No power.
If it idles a bit erratic then check the TPS. Incorrect reading= No Power.

Got any aftermarket goodies on there that may not be installed correctly?

 

it wasn't my exhuast could it be the fuel filter on my gas tank since i just changed the one under the hood? only aftermarket is cold air intake, exhuast, and stereo