The TPS is a switch, and nothing else. All it does so send WOT signal to the ECU
The AFM meter is a potentiometer, and the tracks can become worn. You can move the wiper arm onto Virgin carbon track:
http://youtu.be/-11J8XawQtc
The other thing is to get another, known good ECU. I had the Devils own job with the original motronic 1.1 system I had, and when I finally swapped all the engine loom and management for 1.3, I opened up the old ECUs to find and absolute horror show:
http://www.greatoldone.co.uk/blog/20...here-fast.html