This could be an airleak after the airflow meter, any ventilate dragged in here isn t seen by the ECU and fittingly not compensated for and can lean the engine out and can in addition to allow the engine to rev in the works taking into account not desired causing harsh running. As its a mechanical fault it tends not to aim on the aberration lighthearted and you can sometimes hear a hissing noise in imitation of 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 difficulty history. It currently has a master tech certified idle air govern valve and tps installed. without upsetting anything, the last (used) ecu and my original, would manage in the car without this symptom.
subsequent to I begin the car, the engine surges happening together with 1200 and 2000 rpm urge on and forth. I distorted the IAC and the TPS in the manner of no regulate 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 speed screw to degrade the rpm and it would withhold for a while. Now, the engine is until the end of time surging to the narrowing where I cannot steer it for scare of damage to the steer train. Any experienced solution?