Check the hose clips for tightness and inspect the trunking for any cracks or splits and after that all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best pretentiousness to locate a leak is to have the engine meting out and hot and subsequently spray lighter gas /propane or brake cleaner with reference to each joint in turn. If the engine rev s going on you ve found your leak.
Might then 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 control the engine without it. if the engine condition is the similar subsequently chances are the meter or the association to it is faulty. Its along with worth cleaning the MAF sensor wires, as they can acquire coated like dirt exceeding become old which next offsets the reading. Use some contact cleaner or brake cleaner to spray can onto the wires to sever the dirt on no account adjoin the wires subsequently whatever as they are unconditionally fragile
behind I begin the car, the engine surges stirring along with 1200 and 2000 rpm encourage and forth. I changed the IAC and the TPS in the same way as no modify 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 enthusiasm screw to humiliate the rpm and it would retain for a while. Now, the engine is all the time surging to the tapering off where I cannot drive it for panic of broken to the drive train. Any experienced solution?