I've cleaned my sticking throttle/butterfly valve twice. Both times I did it while the car was not running. This way, I could open the butterfly all the way open and scrub both sides with a rag and toothbrush. Also, scrub the "lip" or "seat", where the valve rests against the body. It worked like a charm, and the car cranked right up with no problems. BTW, I used the Valvoline cleaner.
Oh, and you don't need to have anyone inside the car reving it up - just grab the throttle linkage with your hand and do it yourself.
