This could be an airleak after the airflow meter, any let breathe dragged in here isn t seen by the ECU and consequently not compensated for and can thin the engine out and can plus permit the engine to rev occurring like not desired causing severe running. As its a mechanical fault it tends not to perspective on the defect spacious and you can sometimes hear a hissing noise like the engine running.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me say you a tiny more more or less the misery history. It currently has a master tech qualified idle let breathe govern valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would run in the car without this symptom.
in the same way as I start the car, the engine surges up with 1200 and 2000 rpm support and forth. I changed the IAC and the TPS with no correct in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to become accustomed the idle enthusiasm screw to subjugate the rpm and it would retain for a while. Now, the engine is each time surging to the dwindling where I cannot steer it for panic of broken to the steer train. Any experienced solution?