This could be an airleak after the airflow meter, any let breathe dragged in here isn t seen by the ECU and for that reason not compensated for and can lean the engine out and can as well as permit the engine to rev occurring past not desired causing prickly running. As its a mechanical fault it tends not to slant on the deformity spacious and you can sometimes hear a hissing noise next 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 practically the trouble history. It currently has a master tech attributed idle let breathe rule valve and tps installed. without distressing anything, the last (used) ecu and my original, would govern in the car without this symptom.
in imitation of I start the car, the engine surges happening between 1200 and 2000 rpm assist and forth. I distorted the IAC and the TPS considering no tweak in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to familiarize the idle eagerness screw to demean the rpm and it would withhold for a while. Now, the engine is permanently surging to the narrowing where I cannot drive it for alarm bell of broken to the steer train. Any experienced solution?