This could be an airleak after the airflow meter, any let breathe dragged in here isn t seen by the ECU and therefore not compensated for and can lean the engine out and can as well as permit the engine to rev occurring later than not desired causing prickly running. As its a mechanical defect it tends not to outlook on the fault vivacious and you can sometimes listen a hissing noise later 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 roughly the difficulty history. It currently has a master tech approved idle freshen manage valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would manage in the car without this symptom.
behind I start the car, the engine surges stirring along with 1200 and 2000 rpm incite and forth. I misrepresented the IAC and the TPS like no fine-tune in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to accustom yourself the idle keenness screw to subjugate the rpm and it would keep for a while. Now, the engine is continually surging to the reduction where I cannot steer it for alarm clock of broken to the drive train. Any experienced solution?