On my Freinds 1989 240sx 5 speed, when he starts and runs the car its idles at around 1,800 rpm. I have reset the TPS to .50 volts and took off the EGR plate and AISC connected to it and cleaned it out. but the car is still idling High.
More detail. When the car is first started up it idles fine for 2-3 seconds then teh idle starts creeping up to the 1,800 rpm. what else could be the problem?
no one has any idea’s?
vacuum leak…check the injectors to see if they are snug…
loose ground…
Idle Control?
I also removed the fuel rail and reseated it when I did the EGR plate. I guess I will have to start tracken down vacume lines 
which I am not going to be able to find haha
You could try:
– Cleaning out the IACV with TB cleaner to see if the valve is sticking/dirty
– Ensuring your throttle cable isn’t stuck on anything/sticking or over-tightened & checking to make sure throttle plate closes off throttle
– Ensuring spark plug connections are clean and wires are well-seated
– Seeing if any codes on ECU
Might also be a coolant temperature sensor starting to go. They can cause anything from weird idle issues to a no-start, and don’t necessarily throw a code.