Is there a way to determine this for sure? I've been having a problem recently where the car will idle very very high (at about 2000RPM) and doesn't want to kickdown. It will eventually, but it's not consistent.

I hooked up the scanner to it and the IAC steps last night were at about 100 with the target steps supposed to be at 0. I have already removed the IAC and it was completely clean, so it's not a matter of it being gummed up. And the sensor is only about 10,000kms or less old. (replaced last year).

I unplugged the IAC while the engine is running and the idle speed did not change. So I hooked it up and again, it did not change. Does this mean the little motor is toast? I don't want to replace it if I'm not sure.

What else would cause a high idle?

 

Did you reset the IAC when you installed it and then reset the TPS? With IAC counts of 100 and assuming the engine is up to running temp, open the throttle blades by turning the screw stop till you get around 20-30 counts. After that, reset the TPS to whatever you need it to be. I believe it is somewhere around 0.54V.

Another thing that comes to mind is that you car is trying to get more air. This can be seen by the IAC counts of 100 when it should be around 20-30. What do you have your fuel pressure set at? That could cause it to idle high too.

 

A couple questions come to mind now...

How do you reset the IAC?

When you say reset the TPS, do you mean physically adjusting it (loosen the screws, set closed throttle at .54 and WOT at 4.5)? If so then this part is set okay. At closed it's at .57 and WOT is set at 4.4X...so that should be close enough.

I don't want to play with the idle screw...I say this because the idle will come down to normal (about 650RPM) eventually, but not on a consistent basis. So the minimum idle is not out of adjustment.

The FP is set at 46PSI (with vac disconnected) currently. The fuel pump was jut replaced 2 weeks ago so I know that's in check. It had the high idle problem before the pump was replaced, and still has it afterwards.

 

There are 2 ways. One way is the way I mentioned and the other is the book way. The book way has you short out the ALDL terminals and turn the key to on and the engine off for a minute. You then disconnect the IAC plug and start the car and keep it running and see what RPM you have. Set it to the base number which is around 450 or so for a stock car or whatever it takes to keep just at idle then you shut off and reconnect the plug. Then reset the TPS.

By your counts of 100, it means the ECM is opening the IAC. This is because it is not getting enough air. I would turn the screw till the blades are open enough which is when you have 20-30 counts and then set the TPS.