Very low idle RPM after ignition on 99 lexus ES300

Hi, I have a 99 Lexus ES300, it runs well but the following problem happened a few times in the last 2 years. Idle RPM of this car is normally ~ 750 rpm, and it usually does stay at 750 range. Problem is the idle RPM drops from 750 to ~ 200 or so right after ignition and it picks up after I step down a bit on gas pedal. It happened so infrequent, about three times in the last 2 years, but I am concerned that there is bigger problem if I do not take care of it! What is this problem, exactly? Thanks in advance

There could be a problem with the idle air control circuit. This can be caused from a malfunctioning Idle Air Control motor or a dirty throttle body.

You could bring it in and ask that they remove the IAC motor and clean it and the throttle, but since the problem occurs so infrequently, did it get fixed?


Thanks for the input. I have not taken it to garage, it would help to know how much would it cost for replacing an IAC motor and do a throttle clean job?

Before you have the IAC replaced, do the throttle body cleaning and have the mechanic concentrate on the IAC passages. Sometimes the pintle gets gummed up and sticks in the low air position, especially after a long hard run and then cool down. A good cleaning will usually free it up.

The IAC part is fairly expensive. The throttle body cleaning will probably be less than $100. You can query the service writer about what they would charge for the above but re;ate only the symptoms and let them diagnose the fix.

Hope that helps.