2000 Avalon, fast idle problem

[AlexM42]

In the last two days a real strange problem has come up on my car. I noticed the engine was idling about 1100 rpm while i was stopped at a light. As soon as the light changed and I stepped on the gas, it seemed fine Then a few mile or two later I noticed it doing it again. This time I released the brakes but did not step on the gas. The idle immediately dropped but the car surged forward just for a split second as the idle was dropping.
The next time it happened, I put the car in neutral, with the brakes on, to see what the RPM would be. It jumped up to about 2500 RPM. Just out of curiosity, I stepped harder on the brakes. The harder I stepped the more the RPM went up. When it went over 4000 I released the brakes. The idle immediately dropped to normal. I put it in drive and it drove normally. The next day it did it a few times. Anyone ever hear of this problem? Light brake pressure easily holds the car from moving forward.
Thanks

Alex

[AlexM42]

Well, apparently it wasn't the idle control valve. It was replaced by the shop for $399.
I have received no answers here. No one else has ever seen this problem?
I suspect the power brake booster is leaking but it only happens every few days.
A new one is well over $600. Rebuilt is about $250. Has anyone here had experience with a rebuilt booster on an Avalon?
Thanks

[AlexM42]

Well it was the power booster, just as I suspected. I bought a rebuilt unit for about $250 and put it on in about 6 hours. No problems since then.

[pmesfun]

Try cleaning the throttle body with throttle body cleaner.
DIY:
How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures

[Warsaws]

Originally Posted by pmesfun

Try cleaning the throttle body with throttle body cleaner.
DIY:
How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures

I'm confused. I thought he solved his problem?

[pmesfun]

OHHH, wow,, I read it wrong.