Why does 2005 Avalon idle high when cold?

Tiny
GRBAY
  • MEMBER
  • 2005 TOYOTA AVALON
  • 75,000 MILES
On possibly bad advice from a mechanic, I spray-cleaned the throttle plate on my 2005 Avalon XLS. Immediately following that move, it started idling at about 1800RPM when cold (50 degrees F.) After about 4-5 miles of driving, it drops to normal idle speed. Everything's re-attached properly, and the vacuum lines are all hooked up. I can find no vacuum leaks. (Does this model even have an Idle Air Control Valve?)
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Friday, November 25th, 2011 AT 5:31 PM

7 Replies

Tiny
FIXITMR
  • MEMBER
What was the reason for cleaning in the first place? Was there a problem?
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Friday, November 25th, 2011 AT 6:22 PM
Tiny
GRBAY
  • MEMBER
Starts from a standstill were rather******. The mechanic told me that they usually clean the throttle plate at around 100,000 miles. I'm below that, but thought it might help. He had said that, as it's a drive-by-wire, sticky plates arent felt as readily (through the accelerator) as cable controls. My starts actually do seem smoother, but the cold idle is driving me crazy.
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Friday, November 25th, 2011 AT 7:09 PM
Tiny
FIXITMR
  • MEMBER
Did you unplug it to do cleaning? Cause that's a no-no.
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Friday, November 25th, 2011 AT 7:22 PM
Tiny
GRBAY
  • MEMBER
Unplug what? The throttle? No.
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Friday, November 25th, 2011 AT 7:46 PM
Tiny
FIXITMR
  • MEMBER
Any possibility you created an air leak in the process of re-assembly?
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Saturday, November 26th, 2011 AT 11:54 PM
Tiny
GRBAY
  • MEMBER
I didn't actually remove the throttle body, just all the air-cleaner stuff ahead of it. That's all put back together nice and snug, and all the hoses and tubes are tight. As this is drive-by-wire, with no idle air control valve, I'm thinking that, for some reason, the throttle is opening too far when cold. It could be a temperature sensor, but I can't imagine any scenerio where a very cold engine was supposed to idle at 1800RPM. I dread going to the dealer. They'll undoubtedly want to replace things like the throttle control or the ECM. I re-disconnected the battery again overnight to see it something might re-set, but no go.
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Monday, November 28th, 2011 AT 5:22 PM
Tiny
FIXITMR
  • MEMBER
Actually 1800 as cold idle is not unheard of on many cars. I wonder if cleaner contaminated micro electrical circuits in Tbody?
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Monday, November 28th, 2011 AT 5:42 PM

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