The TPS will not cause the throttle to stick wide open (which is what happened). The throttle is controlled by a cable that attatches from the foot pedal to the throttle body -- it is a mechanical setup. The TPS is a rheostat sensor that tells the computer how far the throttle body is open.
It sounds to me that there is either a problem with the throttle body or the throttle cable.
With the engine off - disconnect the throttle cable from the throttle body. Operate the butterfly valve on the throttle body by hand. Check for smooth operation while opening and closing. If it sticks at any position it must be replaced. DO NOT grease - oil - or clean the throttle butterfly.
Check the cable in the same manner, make sure it is operating smoothly -- and make sure that a floor mat is clear of the throttle pedal.
The back fire probably came from the over-reving of the engine. The only way for that to happen is the throttle was stuck or pressed wide open.
Friday, November 27th, 2009 AT 7:02 PM