Check the hose clips for tightness and examine the trunking for any cracks or splits and with every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretension to locate a leak is to have the engine handing out and hot and subsequently vaporizer lighter gas /propane or brake cleaner approximately each joint in turn. If the engine rev s stirring you ve found your leak.
Might as a consequence be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can accomplish a fast deviation locate if you unplug the meter and govern the engine without it. if the engine condition is the thesame next chances are the meter or the relationship to it is faulty. Its then worth cleaning the MAF sensor wires, as they can acquire coated next dirt beyond get older which then offsets the reading. Use some read cleaner or brake cleaner to spray onto the wires to separate the dirt on no account be adjacent to the wires subsequent to whatever as they are unconditionally fragile
bearing in mind I start the car, the engine surges stirring with 1200 and 2000 rpm encourage and forth. I untouched the IAC and the TPS in the same way as no correct 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 quickness screw to subjugate the rpm and it would support for a while. Now, the engine is permanently surging to the lessening where I cannot drive it for terrify of broken to the drive train. Any experienced solution?