This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and so not compensated for and can lean the engine out and can moreover permit the engine to rev going on as soon as not desired causing rough running. As its a mechanical defect it tends not to slant upon the oddity spacious and you can sometimes hear a hissing noise subsequent to 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 little more more or less the misery history. It currently has a master tech endorsed idle ventilate control valve and tps installed. without moving anything, the last (used) ecu and my original, would rule in the car without this symptom.
in the manner of I start the car, the engine surges taking place surrounded by 1200 and 2000 rpm back up and forth. I distorted the IAC and the TPS behind no change in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to become accustomed the idle promptness screw to degrade the rpm and it would hold for a while. Now, the engine is continuously surging to the reduction where I cannot drive it for clock radio of broken to the steer train. Any experienced solution?