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 9:31 AM
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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 10:22 AM
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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 11:09 AM
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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 11:22 AM
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GRBAY
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Unplug what? The throttle? No.
Nov 25, 2011 at 11:46 AM
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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 3:54 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 9:22 AM
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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 9:42 AM
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