This could be an airleak after the airflow meter, any air dragged in here isn t seen by the ECU and consequently not compensated for and can lean the engine out and can plus permit the engine to rev stirring in imitation of not desired causing severe running. As its a mechanical deformity it tends not to turn on the defect blithe and you can sometimes hear a hissing noise taking into consideration the engine running.
Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can get a quick deformity find if you unplug the meter and run the engine without it. if the engine condition is the thesame subsequently chances are the meter or the association to it is faulty. Its moreover worth cleaning the MAF sensor wires, as they can acquire coated like dirt greater than period which later offsets the reading. Use some entre cleaner or brake cleaner to vaporizer onto the wires to surgically remove the dirt on no account adjoin the wires similar to everything as they are completely fragile
subsequently I start the car, the engine surges stirring with 1200 and 2000 rpm support and forth. I distorted the IAC and the TPS taking into consideration no fine-tune in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to get used to the idle rapidity screw to degrade the rpm and it would keep for a while. Now, the engine is at all times surging to the point where I cannot steer it for apprehension of damage to the drive train. Any experienced solution?