I too am having this problem, getting the TPS code. I have two of the same cars so I swapped the TPS from the other car (no codes on that car) and, although it seemed OK at first, no change. In my case, when it won't start, I don't get any power to the Idle Control Valve (ICV). I'm suspecting a bad ground (which would seem appropriate in your case since you're drawing a ground error). However, I'm not sure where the ground(s) are (e.g. for the computer, etc)? Perhaps we can help each other. Any idea where the ground conections are for the engine and computer?
Ed