Reduce engine power

What is your question?

I have a 2002 Chevy Avalanche 1500 2wd. I have change the TAC mod, throttle position sensors and throttle valve. It reads that the sensors are bad. At first it was just one code one sensor. Now its both sensor and all the codes that will pop up for the throttle. Any body with any insight?

What makes this problem better or worse?

From start up

How long has your 2002 Chevrolet Avalanche 1500 had this problem?

Few weeks