Check the hose clips for tightness and inspect the trunking for any cracks or splits and with all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best mannerism to locate a leak is to have the engine management and hot and next spray lighter gas /propane or brake cleaner vis--vis each joint in turn. If the engine rev s taking place you ve found your leak.
Might afterward be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can pull off a quick deviation locate if you unplug the meter and manage the engine without it. if the engine condition is the thesame after that chances are the meter or the attachment to it is faulty. Its after that worth cleaning the MAF sensor wires, as they can get coated once dirt higher than grow old which next offsets the reading. Use some right of entry cleaner or brake cleaner to spray can onto the wires to surgically remove the dirt upon no account be next to the wires subsequent to anything as they are completely fragile
subsequently I begin the car, the engine surges taking place surrounded by 1200 and 2000 rpm support and forth. I misrepresented the IAC and the TPS gone no correct in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to acclimatize the idle speed screw to lower the rpm and it would hold for a while. Now, the engine is continually surging to the reduction where I cannot drive it for terror of damage to the drive train. Any experienced solution?