This could be an airleak after the airflow meter, any expose dragged in here isn t seen by the ECU and correspondingly not compensated for and can lean the engine out and can then allow the engine to rev stirring subsequently not desired causing coarse running. As its a mechanical oddity it tends not to aim on the malfunction lively and you can sometimes hear a hissing noise in the same way as 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 little more very nearly the difficulty history. It currently has a master tech endorsed idle freshen govern valve and tps installed. without distressing anything, the last (used) ecu and my original, would run in the car without this symptom.
like I begin the car, the engine surges in the works along with 1200 and 2000 rpm help and forth. I misused the IAC and the TPS once no regulate 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 swiftness screw to lower the rpm and it would support for a while. Now, the engine is continually surging to the point where I cannot steer it for dread of broken to the drive train. Any experienced solution?