Hello, I have repaired higher than 30000 vehicles in my career and I dependence to ask you questions before I am not there in person to build up facts, data, or to exam your vehicle. I may question you to doing investigation in my stead. If scrutiny is needed and you would rather not put on an act testing, I can present my best advice, Fuel pressure?
Its plus worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not a hundred percent pump will all result in insufficient fuel instinctive delivered to the engine. Might as well as be worth cleaning out the idle readiness direct motor / valve as these acquire clogged taking place subsequent to carbon and some brake cleaner washed through helps clear things off.
next I begin the car, the engine surges happening amid 1200 and 2000 rpm back up and forth. I misused the IAC and the TPS gone no correct in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to adapt the idle speed screw to degrade the rpm and it would maintain for a while. Now, the engine is continually surging to the dwindling where I cannot drive it for siren of broken to the drive train. Any experienced solution?