High idle

[john cris]

Hey
Been 100 degrees everyday for the last week. During that time the idle rpm when put in park stays above 1200. Usually it drops down to 800. Possible vacuum leak made worse by the higher ambient temperatures? IAC? Throttle cable?
Just looking for possible causes. Ideas?

 

[iowa_hick]

Mine was idling up around 1800 rpm, but dropped down to 800-900 after I cleaned the MAF sensor.

 

[john cris]

Mine was idling up around 1800 rpm, but dropped down to 800-900 after I cleaned the MAF sensor.

Just today it returned to normal. I should at least clean the MAF and IAC

 

[john cris]

For way too long I’ve had the problem described at the start of this thread. At long last it has been solved. While the only symptom I noticed previously was the high idle at cold start up in the last few days that changed. In addition I noticed throttle response seemed sluggish. It just didn’t seem to accelerate as smoothly and didn’t drop down to idle as smoothly when up to normal temp. It also began to show the high idle more consistently. So I scanned it and found code 1506 showing. Which is throttle position sensor out of range. I replaced the sensor and the high idle, especially at cold start, has not resurfaced. Looking back on this I’m not sure why I didn’t just replace that sensor to begin with. Anyway, problem is gone and I hope to never see it again
Hope this helps

 

[CDW6212R]

Well done, you got it fixed. I would have cleaned the IAT and watched the coolant temps. Very high coolant temps will raise the idle to cool better, I've had that happen once before. The TPS rarely fails, so finding it with a code is the ideal way to catch it.

Don't ever clean the MAF, people need to leave those alone. They are very fragile, and the only thing that should hurt them is running the engine without a filter, or having a wet filter(K&N) in it. Under proper conditions, the MAF never sees any debris that can stick to it.

 

[john cris]

Well done, you got it fixed. I would have cleaned the IAT and watched the coolant temps. Very high coolant temps will raise the idle to cool better, I've had that happen once before. The TPS rarely fails, so finding it with a code is the ideal way to catch it.

Don't ever clean the MAF, people need to leave those alone. They are very fragile, and the only thing that should hurt them is running the engine without a filter, or having a wet filter(K&N) in it. Under proper conditions, the MAF never sees any debris that can stick to it.

Well done, you got it fixed. I would have cleaned the IAT and watched the coolant temps. Very high coolant temps will raise the idle to cool better, I've had that happen once before. The TPS rarely fails, so finding it with a code is the ideal way to catch it.

Don't ever clean the MAF, people need to leave those alone. They are very fragile, and the only thing that should hurt them is running the engine without a filter, or having a wet filter(K&N) in it. Under proper conditions, the MAF never sees any debris that can stick to it.

Why do you think it took so long for the ecu to set that code? Scanned many times, never showed. TPS not far enough out? Or maybe the coolant temp like your thinking plays a part. Each time I’ve scanned it previously I always got code indicating a coolant temp sensor issue. At which I changed the thermostat, coolant and the sensor, to no avail. It’s strange too since replacing the TPS I’d swear the 5r55w tranny shifts better.
Stay safe

 

[CDW6212R]

The TPS probably didn't fail in an instant, but over a period of time got worse. The coolant temp code was unrelated, but you did the right thing and worked the problems as you found them.

 

[blue xlt]

I had a gates thermostat fail in the open position in about one year, poor heat, replaced with a Stant stat and haven't had a problem since. Your stat may not have been opening fully causing high idle.

 

[john cris]

I agree the thermostat could be involved. When this first started the ecu set a code indicating thermostat not operating properly. At which point I flushed the system, replaced the thermostat and temp sensor. While that cleared the code the high idle at cold start continued