I have a 454 Tbody bored to 54mm. I have had a problem with the it not returning to full closed position while the engine is running and I let off the pedal. When the engine is off I can depress the pedal or rotate the throttle shaft and let off and It will return to full closed position. It seems to be sticking / binding under vacuum and it returns to 2-3 tps when letting off while running/ I can blip the pedal and it will close. Whats the fix??? I purchased it as rebuilt and bored to 54mm 454 tbody. Thanks if anyone has a simple solution I'd truly appreciate it.

 

Been searching about the same problem. Seems the only answer, that has been verified as solving the problem, is to lube the shaft of the throttle body with PB Blaster. Opening it and closing it while you spray to work it in. Let us know if it works.

 

I tried the PB Blaster, and it has seemed to work. I went for a little rip and no stuck throttle. For me it was sticky at idle, and i had to mash the pedal to get it to move (real head snapper), it would also stick at about 2000 rpm as i was coming to a stop. (Luckily i have a clutch) a little blip and she closed. It would also only do this while running. The throttle was free when car was off. I sprayed PB on the TB shaft and down the throttle cable. I am not sure about the results as i only went for a 15 minute ride, but it felt alot better, and no sticking throttle. May only be a temp. fix, might need a TB rebuild or new cable. I can only wait and see. Apparently throttle body cleaner will clean the lube off of the bushings.

For all. I am a new owner of an IROC, and I had one growing up. This message board is absolutely awesome. Great advice and know how, and more importantly awesome rides. To all who contribute, Thanks.