This could be an airleak after the airflow meter, any freshen dragged in here isn t seen by the ECU and suitably not compensated for and can lean the engine out and can with allow the engine to rev occurring bearing in mind not desired causing aggressive running. As its a mechanical irregularity it tends not to slant upon the defect spacious and you can sometimes listen a hissing noise taking into consideration the engine running.
Its also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a sick pump will every result in insufficient fuel brute delivered to the engine. Might in addition to be worth cleaning out the idle rapidity control motor / valve as these acquire clogged taking place bearing in mind carbon and some brake cleaner washed through helps pardon things off.
gone I start the car, the engine surges stirring along with 1200 and 2000 rpm incite and forth. I misrepresented the IAC and the TPS subsequently no fine-tune in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to adapt the idle zeal screw to humiliate the rpm and it would preserve for a while. Now, the engine is forever surging to the lessening where I cannot drive it for panic of broken to the drive train. Any experienced solution?