Check the hose clips for tightness and inspect the trunking for any cracks or splits and then every 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 dispensation and warm and next vaporizer lighter gas /propane or brake cleaner on each joint in turn. If the engine rev s up you ve found your leak.
Its afterward worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a sick pump will every upshot in insufficient fuel beast delivered to the engine. Might also be worth cleaning out the idle enthusiasm govern motor / valve as these acquire clogged taking place later than carbon and some brake cleaner washed through helps clear things off.
later than I start the car, the engine surges in the works together with 1200 and 2000 rpm incite and forth. I misused the IAC and the TPS bearing in mind no tweak in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to acclimatize the idle promptness screw to lower the rpm and it would support for a while. Now, the engine is until the end of time surging to the point where I cannot steer it for dread of broken to the steer train. Any experienced solution?