codes p0123a p1120a 2003 chevrolet trailblazer ltz 4.2 liter

Question

replace motor and computer in 03 trailblazer.  had computer flashed and now it runs but only at idle speed. replaced throttle body and still get codes p0123a p1120a p1220a  reduced engine power is also lit up  throttle position sensor is also saying circuit high voltage. any help will be appreciated