High Idle!

[firefighter72012]

Depending on how much you drive the car everyday, is how many times it happens. Car will idle high in park or when driving. when you are driving the car, and you come up to a stop sign, the car will tend to want to go and not stop, you have to apply the brakes to keep it from moving because of it idleing high. anyways, when you put the car in park it will idle high over 1500rpms, so what is the problem? have had several tech's tell me that it could be the air idle control moter, or the TPS censor being bad or the computer even being bad, because the car shows no errors on the computer, someone please help me with this problem thanks!

[BNaylor]

A bad or dirty IAC will give a high idle. Easiest thing to do is clean the IAC valve. Remove it and clean the spring loaded pintle and the seat at throttle body with carb or throttle body spray cleaner. A lot of soft carbon builds up. Common for no error code to show.

[firefighter72012]

okay i will try that, what about the TPS sensor and stuff, do i need to check that to see if it is bad or what, or is there anything else i should try befor i spend money on it. i don't want to spend $300 yo $400 on somthing that is not going to fix it. Could it hurt my car if i wait to get it fixt or whatever, a tech at automotive shop told me that it won't hurt anything but it is not good for the engine though!

[BNaylor]

Originally Posted by firefighter72012

okay i will try that, what about the TPS sensor and stuff, do i need to check that to see if it is bad or what, or is there anything else i should try befor i spend money on it. i don't want to spend $300 yo $400 on somthing that is not going to fix it. Could it hurt my car if i wait to get it fixt or whatever, a tech at automotive shop told me that it won't hurt anything but it is not good for the engine though!

On the TPS if you have a multimeter you can check its operation electrically. The PCM provides a reference voltage of around 5 volts at one of the pins on the electrical connector so you can check that. The TPS output in return sends a voltage back to the PCM/ECU module. At idle it is around .4 volts. At full open throttle or WOT around 4.0 volts. In between the voltage will progress and be linear as you vary the accelerator towards WOT. Normally a bad TPS will throw an error code.

I suppose you can get by with a high idle for awhile but it must be rough on the tranny when you go from park to reverse or into any forward gear initially.