That's kind of what I was thinking as well. I'll need to find a reliable schematic so I know what wire is supposed to get what signal.
A mechanic friend (out of state) suggested I go ahead and take it into a shop that has a true diagnostic computer (not just a code-reader) and see what signals may be being sent to the throttle body - thinking (without seeing the car) that there may be a possibility of a pooped out computer circuit, physical wiring problem, or something wrong with the accelerator pedal (and it's circuitry) itself, since the car goes into shutdown mode when the accelerator pedal is touched - and also never does truly find a proper idle with the new TB installed.
The backfiring through the airbox - he indicated was an indication of too much fuel - but he didn't think it was a timing belt issue - because other codes would be thrown.
(Also - the previous owner has a receipt from the dealer changing the timing belt, tensioner, and water pump at 117,000 miles (the car has 137,000 on it now) - so it's unlikely to be a timing belt problem)
I'll do what I can before taking it in....
Thanks for the suggestions - If more come to mind - please post. I'll follow up with my findings.
Rex S.