1997 - 2001 Toyota Camry 5SFE Cold Start / Idle Air Control (IAC) Stall Problems

A common but simple cold weather problem with the 4 cylinder 5SFE model Camry is the Idle Air Control (IAC) valve sporadically sticking. This value should close during cold engine start up to restrict air flow. Restricted air flow will provide a rich air/fuel mixture and prevent engine stalls. A rich mixture should normally result in a higher than normal idle speed (approximately 1,400 - 1,600 rpm's). The rpm's will drop as the engine warms up. If your cold engine starts and stays at around 850 rpm's then eventually stalls, the IAC is stuck in the open position due to carbon and varnish buildup accumulated by blow by gases. This buildup can be dissolved by spraying carburetor cleaner solvent in the IAC port which is located as a small rectangular port opening in the mouth of the throttle body. Access to this port can be made by disconnecting the Throttle Body to Airbox Hose Clamp, twisting and pulling the hose off and then pushing the hose away from the throttle body opening. Apply a liberal amount of solvent in the port opening. Re-connect the hose and turn-on and off the engine a few times to allow the IAC valve to work loose the carbon and varnish build up. As the solvent is being burned off, some smoke will blown out through the exhaust pipe.  If non of the above fixes the problem, consider replacing the IAC which will require removal of the throttle body assembly.

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Comments 12 comments

david 5 years ago

I repeat the process ( exactly as hardlymoving mentioned ) 3 times. The result is ideal. Thank you hardlymoving !!!

david 5 years ago

Just add this: I went to the Auto Zone have them use the handheld computer checked (because the engine light was on). The code number the computer give out is P0172 (nothing mentioned on the compter list to do with this process).

The Symptom is: 1. the car stalls when I am driving from highway and stopps at the stop light. And 2. the car stalls when I start the car and back up while the car is warm (after driving for a while).

Thank you hardlymoving !!!

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RUNXCTRY 5 years ago

When starting my car in cold weather, my car starts, and the RPMs drop steadily within 3-5 seconds until the car stalls. I can rev the engine, hard, so that the idle controller (or whatever) kicks in and maintains steady engine speed.

Can't wait to try this fix, then wait for a cold day.


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hardlymoving 5 years ago from Memphis, TN Author

Stuck IAC valves are common on Camrys ... the fix is easy and straight forward.

doug 3 years ago

would the iac cause rpm flux during warm weather?

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hardlymoving 3 years ago from Memphis, TN Author

Not that I've seen. When they clog, rpm never rises ... and when the engine is cold, the car stalls until warmed up. You've probably have a vacuum leak. Check your Air Filter to Throttle Body Air Hose for cracks and all vacuum tubes.

ajith 23 months ago

I have 2001 Camry v6. during start irrespective of outside temperature RPM will abe around 1500-1800 rpm. it takes 10 mins to come to normal rpm 700-800 . Car runs smooth is it normal ?

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hardlymoving 23 months ago from Memphis, TN Author


Yes ... that is normal until the engine warms up.

Psalm37 22 months ago

I also have an 01 Camry with the same fast idle. I plan to sub in a 5 speed manual, and would like to by-pass the fast idle, or at least bring it down by about 500 rpms. Is there some computer fix for this?? Thanks a lot!!

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hardlymoving 22 months ago from Memphis, TN Author


Doesn't matter if the car's an automatic or manual. The fast idle is controlled by the car's computer to enrich the air/fuel mixture (to prevent cold engine stall) resulting in high rpm's. The rpm's will gradually go down as the car warms up. I believe the coolant supply and return hoses to the throttle body allows the Idle Air Control valve (IAC) to monitor the engine temperature. As the temperature rises, the idle speed will diminish.

James 19 months ago

My Camry idle fluctuates after 30min (btw 800 and 900) especially in traffic. When I try to move the car goes off.

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hardlymoving 19 months ago from Memphis, TN Author


Could be a lot of issues ... but most likely your A/C unit engaging and disengaging to control your interior cooling temperatures. When it engages, it puts a load on your engine, the rpm's drop and the car's computer will compensate by raising the idle.

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