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2003 Camry 2AZ−FE Very Fast Idle


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After repairing a leaking head gasket due to stripped head-bolt threads in block, the engine now idles way too fast.
Its around 1400 RPM on starting, eventually rising to 2100 RPM whilst idling in neutral. Drops to 1100 RPM when Drive is engaged.

I have checked for leaks around the inlet manifold, injectors and throttle body and found none (all new gaskets fitted during rebuild).
Also checked hoses for any cracks or splits.

Removed throttle body, cleaned it and checked operation of butterfly valve.
Also checked that the resistance range of the TPS was within spec.
I then tried to get the ECM to relearn the correct idle speed by following several of the suggested methods found via Dr Google but without success.

Finally I pulled the electrical connector from the IAC valve whilst the engine was running and the idle speed immediately dropped to 1400 RPM.

I suspect a problem with the IAC valve but before I pull it apart or buy a replacement I am consulting the collective wisdom of the members of this forum.

Any ideas?


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Problem Solved

I checked and cleaned the PCV valve with TB cleaner and ensured it was working correctly before installing it back into the valve cover.

Next I checked the inlet manifold vacuum and found it to be 17 in Hg on a cold start, rising steadily to 22 in Hg as the engine reached operation temperature.
This is in accordance with the data published in the Haynes workshop manual.

Finally it was time to check to IAC (Idle Air Control) valve. Luckily it could be removed from the car without again removing the throttle body.
It was full of black gunk which I removed with lots of TB cleaner and a small brush.
I then removed the electric actuator from the IAC to check and ensure that the valve could move freely on its shaft.


IAC Valve Body and Actuator

After reassembly I installed the IAC valve on the TB in the car and plugged in the electrical connector.

Upon starting the engine the idle revs went to 1000 RPM and then steadily dropped to around 650 RPM. Joy!

Did some extensive test driving and stopping to check idle, but its perfect.

So to sum up, happy camper, after Camry being off the road for 2 months.

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Good to know that you were on the right track.

I had the exact opposite issue with the IAC valve on my 1998 Camry. It would not idle without accelerator and this was after running very nicely for that Sunday drive.

In 10+ years of ownership and about 150,000 kms, I had never known to clean the throttle body and IAC valve. A few Google searches got me on the right track and now I clean the throttle body and IAC valve regularly on my current vehicles.

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