Aphix

I own a 99 TL that has been idling high after either sitting in park for too long or driven in hot weather, sometimes even before its been driven if its over 85ish. It doesn't seem to be overheating because the guage never crosses 50 percent (theres no numbers to go by). Can anybody shed some light on this?

goldendragon576

how high is high? What does it idle at?

Aphix

Well it'll start at about 1100 RPMs, then 1500, and then the other day I didnt have a chance to turn it off for awhile and when I put it in park it was at 3000 RPMs before I turned the car off.

fsttyms1

Do the RPMs fluctuate up and down or are they just high. One thing to look at is that the Throttle body closes all the the way. Make sure nothing by the cables is binding it open or carbon build up. Is there a check engine light?

other problems could be IACV
or TPS (throttle position sensor, requires a new TB)
vacuum leak.

Aphix

Once it starts its consistent. I have always assumed carbon build up could be avoided by getting up on a car every now and then and I do. I was thinking about the throttle body but I can't see why it would change anything when the car gets hotter. There is no check engine light too. I'm not familiar with the IACV? And a vacuum leak could be the problem, I dont know if maybe there's a vacuum hose that kicks on after a certain temperature or what. The car never overheats though, its always stayed consistently at running temp.

McChicken

Mine fluctuates up and down......What do you suspect is the culprit?

fsttyms1

Iacv

Aphix

What is Iacv?

fsttyms1

That was directed to the post above mine. IACV is Idle Air Control Valve.


Yours probably not due to yours not bouncing up and down. You need ti inspect your TB and make sure its free and clear of carbon build up and deposits. Other wise i woudl suspect a vacuum leak or the TPS sensor.

Aphix

Are there any key spots too look at for a vacuum leak?

Musky-Hunter

Sorry to hijack your thread but tonight mine did this again for the first time since last year. The only thing I see in common when it occurs for me is that every time I am running the AC and it is hot. If I turn off the car it resets. Tonight is the first time it didn't reset after only one restart, it took three.

The mechanic couldn't diagnose becuase it doesn't create an error code and all the sensors read normal by the time I get it to them, at which point is is no longer happening.

Does anyone have any idea why this would only happen when the AC is on?

Aphix

On mine, the AC seems to make it happen faster. And there doesnt seem to be any reset on mine but I will try turning it off and on a few times and see if that works next time. Mine is at the point where I can expect it to happen. In the winter it would start after letting it idle for awhile, and driving it a little would help keep it from doing it.