Why does 2005 Avalon idle high when cold?

2005 TOYOTA AVALON
75,000 MILES
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GRBAY
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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?)
Nov 25, 2011 at 5:31 PM
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FIXITMR
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what was the reason for cleaning in the first place? was there a problem?
Nov 25, 2011 at 6:22 PM
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GRBAY
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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.
Nov 25, 2011 at 7:09 PM
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FIXITMR
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did you unplug it to do cleaning? cause that's a no-no.
Nov 25, 2011 at 7:22 PM
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GRBAY
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Unplug what? The throttle? No.
Nov 25, 2011 at 7:46 PM
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FIXITMR
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any possibility you created an air leak in the process of re-assembly?
Nov 26, 2011 at 11:54 PM
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GRBAY
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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.
Nov 28, 2011 at 5:22 PM
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FIXITMR
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actually 1800 as cold idle is not unheard of on many cars. i wonder if cleaner contaminated micro electrical circuits in Tbody?
Nov 28, 2011 at 5:42 PM