CPI idle stepper motor problems!!!
I've got a 3.9l cpi EA 4sp auto and recently the car has been jumping up to 1500rpm as it's base idle then dropping back to 650rpm whenever it wants. I have checked the TPS all ok, so could it be the power steering pressure switch as per gregorys manual. Any idea's i am pretty sure its not the stepper motor getting stuck because it happens when reversing out of the drive way at idle speed so something is telling the ecu there is a large load on the engine. In the electrical schematic the only sensors which are connected to the tps are Coolant, air temp, map and power steer sensors. Also when i pull the car up when its idling at 1500rpm and put the car into park it drops back to 650rpm then when i put it back into drive and get back on the road it jumps back up to 1500rpm. I have reset the ecu a number of times, checked all earths, fault codes and fuseable links. Any ideas???