My car sucks... please help :(

[Jaleesa]

So I've had an idling issue ever since I bought this hunk of junk GPX. (Had to keep my foot on the pedal for a few mins until it warmed up to hold an idle, and used to idle at about 1100ish). We got a new stepper motor, and the car was pretty great! Started perfect and was smooth through the gears. The elation did not last long. After two blissful drives, the bloody car has decided to murder the new stepper motor; it will no longer idle when I start it. So, we decided to take it off, clean it and put it back on. And then all hell broke loose. It was now idling at 1500 when warm (1100 cold), and as I pulled up at the lights the engine hunted quite erratically for a few seconds before steadying. At this point, I was pretty pissed.

We began to experiment with TPS adjustment, although mainly focused on the stepper again. We tested it with the old one, but to no difference (revs still raising up and no idle), so then I decided to temporarily rob my GR for it's stepper motor, as that car works like a normal vehicle should, and tried that instead.
Big mistake. Huge. The GPX absolutely hated it! Although it starts now without complaint, it instead revs at 1500 cold, and 2000 when its warm
No hunting, thank the lord, but when I go to change gears and put the clutch in, the revs jump up about 250rpm, before coming back again as I get it in the next gear.
Also when I turn the air con fans on, the revs drop considerably at idle, obviously the engine taken on load, but clearly it's not compensating. And the more confusing thing is, when we first put the new stepper motor on it, the revs raised up instead of dropped when I turned the fans on.

We have messed with the TPS a lot (thought it was the stepper motor to begin with hah). I even got a new one and tried that, and it seems to be different in the inner design slightly , however it makes no difference to the running rather than the other one. Apparently you have to have these set/fitted to around 0.6v or something? If so we haven't done that yet, and all the messing around would've put it off position.

Haven't got error codes yet, as the machine is showing a connection issue to the car, so getting those is most likely the next point of action.
We also turned the car on coldish without any stepper motor or TPS connected, and there was no difference at all as to when it did have them on.

So yep, it's either I lose my mind, or I lose the FTO right about now! Any advice or help would be so greatly appreciated!!

[getonit]

Well setting the TPS to its correct position would be a good idea.

[Jaleesa]

Cool thanks, we just set the TPS to 0.62, and it was still climbing the revs until it hit around 1750rpm idling. Didn’t seem to have any effect Could it be something to do with the fuel regulator?

[silverGPX]

Sounds like you put the stepper motor in upside down, yes it is possible..