Warm start rough idle then dies

The idle air control motor (below the throttle housing) gets dirty and sticks, usually causes stalling from cold starts) I have had success cleaning them and my scan tool can test them afterward. It's hard to guess whats wrong without being able to experience the problem first hand and then do some basic tests. I've seen a lot of ignition coil failures but this sets a misfire code, the airflow meter on this Lexus get dirty results in loss of power, fuel economy and also sets a misfire code, could cause idle problem. It could be bad electrical connections hard to tell without being able to do some tests when the car is failing.

The most common cause of your symptoms on the V6 engined Lexus and Toyota models is the I.A.C.V., Idle Air Control Valve. This is the device that, based on engine temp and run time, sets idle speed. The most reliable repair is to replace the valve, as accessing it to clean it takes the same amount of time and cleaning results in less than acceptable long term performance, IMO. You may find that as spring turns to summer, the problem occurs less often, giving you some time to prepare, budget and plan for the repair / replacement. Still, it would be best to confirm the cause of YOUR problem before initiating repairs. We would be pleased to help you if and when you decide to address this or other issues. Foreign Affair Honda Acura Totoyta Lexus, Santa Clara CA 408-727-4884

I would agree with the last two posts. Most likely it is a faulty IAC motor, very common on Toyota/Lexus products. Performing a few simple tests before hand and having the car exhibit the symptom would be inorder before changing any parts.