On your TPS you need to pierce into the signal wire, I know when I ran a L6 that it is the same colour as one of the wires in the phase sensor.
Just peel back the boot on the tps connector, see what colour wires are there, one is the same colour as a wire in the phase wiring(loom not actual sensor) or in any event prod the wires with a multi meter with ignition on, one will be around 4.8/5v, and another earth the last one will be low around 0.6v, this is the signal wire, this is the one that varies with the throttle position, just hook into this wire and look for a dead patch, it is the only wire that varies voltage going to the tps so can't go wrong.
What you are looking for is any positions where the meter loses the reading, due to a duff tps, it is basically a carbon track inside with a wiper arm that sweeps against it, so it wears, sometimes you can give them a little more life by rubbing a HB pencil into the track, but won't last long, just a old trick(showing me age here!!).
Any dead spots means a new one needed, but they are a fairly common resistance and fitting, ie 8mm D shaft, I use a universal one, cost £20 brand new, just needs connector changing.
tabetha