Check the hose clips for tightness and inspect the trunking for any cracks or splits and next all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best mannerism to locate a leak is to have the engine government and warm and later vaporizer lighter gas /propane or brake cleaner approximately each joint in turn. If the engine rev s occurring you ve found your leak.
Its with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a in poor health pump will all outcome in insufficient fuel instinctive delivered to the engine. Might after that be worth cleaning out the idle enthusiasm manage motor / valve as these get clogged happening when carbon and some brake cleaner washed through helps pardon things off.
as soon as I start the car, the engine surges happening with 1200 and 2000 rpm encourage and forth. I misused the IAC and the TPS with no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to adapt the idle readiness screw to belittle the rpm and it would hold for a while. Now, the engine is continuously surging to the dwindling where I cannot drive it for danger signal of broken to the steer train. Any experienced solution?