I went to start my car today and it would not idle. I would start it, it would run for about a half of second and then die. I had to hold the gas down just to get it to idle. After that, the car would finally idle, but it would surge between 800-1200 rpms. It then finally cleared out back to normal. It threw a code for a couple seconds and it came up with TPS 21 code. I already replaced the TPS sensor. I'v been having a feeling my IAC valve is crapping out. I cleaned it and it didnt help. Would a bad IAC throw a TPS code? Help, Im sick of trying to figure this out.
The car still idles at 1300-1400 RPMS when it is warmed up.

Rob

First idea is you may not have disconnected the battery for 30 mins after changing the sensor. That'* the first thing I'd try.

When you replaced the TPS, did you calibrate it? If the TPS voltage is too low or too high, it'll set a code, and that happened to me before I knew that the TPS was adjustable, but I never noticed any symptoms other than an SES light.

Was the TPS code the only code present? Check the electrical connector for the TPS, and if you have access to a scan tool, a scan would probably be helpful.

I did reset the battery multiple times. I did calibrate the TPS also. I get all the correct voltages. I still think its my IAC valve making things screwy. The car started great after work today, and no SES lights.

Rob

At this point, you may want to look for vacuum leaks, clean your maf and IAC to ensure the passages are clean.

Me and my dad checked for vaccuum leaks, I cleaned my IAC and the car has a new MAF.

We have seen a few sensors come out of the box bad. If you are still getting the code for TPS, have checked voltage and tried adjusting/unplugging. Seems that something is amiiss there.

Double check the wiring for bare or rubbed spots going to the TPS/Throttle Body area..besides that..I think it may be a bad sensor.

I'd be curious to see you check the wiring between the TPS and the PCM.

It has only thrown the TPS code once since I put the new one on. I honestly think it threw the TPS code because I was fighting with the car, trying to make it idle. I was pushing the gas pedal down while the idle surged back and forth. It then cleared out. Before I replaced my TPS, my old one was throwing the code constantly. The car did idle normal before I took the thottle body off, cleaned it and the IAC, and put on the new TPS sensor. I even took the throttle body off a second time and replaced the gasket. Still problems. Would the computer throw a code for the IAC if it was bad/malfunctioning?


Rob

I just realized when I start my car from a cold start, it idles only at 900-1000rpms. When my car warms up, thats when my idle gets to 1400 RPMS. It seems like its doing the opposite of what its suppose too.

Thanks,

Rob