Check the hose clips for tightness and inspect the trunking for any cracks or splits and as well as 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 admin and hot and later vaporizer lighter gas /propane or brake cleaner roughly each joint in turn. If the engine rev s in the works you ve found your leak.
Its as well as 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 every upshot in insufficient fuel swine delivered to the engine. Might then be worth cleaning out the idle readiness manage motor / valve as these get clogged up taking into account carbon and some brake cleaner washed through helps free things off.
behind I start the car, the engine surges occurring along with 1200 and 2000 rpm incite and forth. I tainted the IAC and the TPS similar to no bend in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to adjust the idle zeal screw to demean the rpm and it would maintain for a while. Now, the engine is continuously surging to the reduction where I cannot steer it for dread of broken to the drive train. Any experienced solution?