Check the hose clips for tightness and examine the trunking for any cracks or splits and then every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best exaggeration to locate a leak is to have the engine dealing out and warm and subsequently vaporizer lighter gas /propane or brake cleaner on each joint in turn. If the engine rev s taking place you ve found your leak.
Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a fast idiosyncrasy find if you unplug the meter and direct the engine without it. if the engine condition is the similar subsequently chances are the meter or the relationship to it is faulty. Its next worth cleaning the MAF sensor wires, as they can get coated considering dirt more than grow old which then offsets the reading. Use some right to use cleaner or brake cleaner to spray can onto the wires to cut off the dirt upon no account lie alongside the wires taking into account everything as they are unquestionably fragile
taking into account I start the car, the engine surges occurring amid 1200 and 2000 rpm back and forth. I changed the IAC and the TPS past no bend in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to get used to the idle rapidity screw to demean the rpm and it would retain for a while. Now, the engine is continually surging to the narrowing where I cannot drive it for buzzer of broken to the steer train. Any experienced solution?