On Jan 2, 6:22 pm, "Ray O" <rokigawaATtristarassociatesDOTcom> wrote:
> <akc...@yahoo.com> wrote in message
>
[quoted text clipped - 31 lines]
> Ray O
> (correct punctuation to reply)
You didn't say what model Lexus you have or with how many miles, but
it could also be the idle speed control valve sticking.
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Good point, although a sticking idle air control valve will often also cause
poor idling even after the car is started.
I didn't list other possible causes in my original response because I wanted
to know the mileage and maintenance history first, but here are some other
possible causes in addition to the sticking idle air control valve; dirty or
clogged MAF sensor, dirty or clogged air filter, disconnected wiring,
problem with the coolant temperature sensor for the ECU and associated
wiring; worn spark plugs; problem with the ignition system, problem with the
fuel delivery system, vacuum leak, leak in the intake snorkel between the
air filter and throttle body; restriction in the exhaust.
More information from the OP would make diagnosis a little easier.

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Ray O
(correct punctuation to reply)