Check the hose clips for tightness and examine the trunking for any cracks or splits and plus 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 admin and warm and subsequently spray lighter gas /propane or brake cleaner in relation to each joint in turn. If the engine rev s stirring you ve found your leak.
Its moreover worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not at your best pump will all outcome in insufficient fuel subconscious delivered to the engine. Might after that be worth cleaning out the idle promptness manage motor / valve as these get clogged in the works as soon as carbon and some brake cleaner washed through helps release things off.
next I start the car, the engine surges up amongst 1200 and 2000 rpm put up to and forth. I misused the IAC and the TPS taking into account no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to get used to the idle rapidity screw to humiliate the rpm and it would withhold for a while. Now, the engine is continually surging to the tapering off where I cannot steer it for distress signal of broken to the drive train. Any experienced solution?