I need your help guys
What I have: LQ4/ 01' T/A Harness/ 99' T/A PCM in a 240sx

Problem: Upon start up idles at around 3k rpm's and does not idle down. (I have only let it run for a minute or so)
I am getting the code P0122 Throttle position sensor circuit low voltage (immature)

What I have done:
Replaced sensors-TPS (cleaned housing before installing new and checked wire integrity into the harness about 12"), IAT, CTS.
PCV system replaced (no leaks)
Voltage at TPS connector on harness is present and sufficient
When scanning via HPtuners TPS % fluctuates during throttle movement
Map sensor is within normal limits (No codes)

It runs great with the exception of the idle being high, no other codes. I have not driven the car yet (New clutch and I don't want to be stuck at 3k all the time/ damage something)

 

Bump, I have the day off and I need some ideas.. thanks

 

There are TPS idle parameter tables in HPTuners that you can tweak but I am not 100% sure what you need to do to them. Have you posted or searched over on the HPtuners forums?

 

I have considered adjusting the idle parameters, but my only discrepancy against that is, i don't want to tune around a fixable problem (Kind of like putting a band aide on a gun shot wound..) I will definitely check out HPtuners for some advice thanks tording99z28

 

The PCM no longer is giving any codes.
But still starts up with rpms at 2800 and slowly climb to 3200...
Could it be the different comp ratio between the LQ4 9.4:1 and the LS1 PCM's higher ratio? (I changed the cylinder volume and engine size from 5.7 > 6.0)

 

I am trying a new IAC valve, I cleaned the one I have, but its the only sensor I haven't replaced. Also it doesn't move with the ignition on.. or with me manually pressing on it.. Its worth a try.

 

The new IAC valve fixed it! Thanks.