Check the hose clips for tightness and inspect the trunking for any cracks or splits and then all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretentiousness to find a leak is to have the engine giving out and hot and then spray lighter gas /propane or brake cleaner with reference to each joint in turn. If the engine rev s taking place 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 get a quick malformation locate 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 connection to it is faulty. Its furthermore worth cleaning the MAF sensor wires, as they can acquire coated gone dirt higher than mature which then offsets the reading. Use some entry cleaner or brake cleaner to spray can onto the wires to remove the dirt on no account adjoin the wires taking into consideration whatever as they are entirely fragile
once I start the car, the engine surges occurring in the middle of 1200 and 2000 rpm help and forth. I untouched the IAC and the TPS next no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to familiarize the idle rapidity screw to degrade the rpm and it would hold for a while. Now, the engine is until the end of time surging to the point where I cannot drive it for terrify of broken to the drive train. Any experienced solution?