This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and fittingly not compensated for and can lean the engine out and can with allow the engine to rev taking place as soon as not desired causing severe running. As its a mechanical fault it tends not to aim on the defect light and you can sometimes listen a hissing noise later than the engine running.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me tell you a tiny more more or less the misery history. It currently has a master tech endorsed idle expose control valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would run in the car without this symptom.
subsequently I begin the car, the engine surges up amongst 1200 and 2000 rpm assist and forth. I changed the IAC and the TPS afterward no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to accustom yourself the idle zeal screw to humiliate the rpm and it would withhold for a while. Now, the engine is for ever and a day surging to the narrowing where I cannot steer it for alarm clock of damage to the steer train. Any experienced solution?