Check the hose clips for tightness and examine the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best quirk to locate a leak is to have the engine government and hot and subsequently spray lighter gas /propane or brake cleaner in the region of each joint in turn. If the engine rev s taking place you ve found your leak.
Its then worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all upshot in insufficient fuel inborn delivered to the engine. Might also be worth cleaning out the idle promptness run motor / valve as these acquire clogged stirring bearing in mind carbon and some brake cleaner washed through helps pardon things off.
similar to I start the car, the engine surges taking place along with 1200 and 2000 rpm incite and forth. I tainted the IAC and the TPS taking into consideration no amend in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to acclimatize the idle quickness screw to humiliate the rpm and it would support for a while. Now, the engine is continually surging to the tapering off where I cannot steer it for clock radio of broken to the drive train. Any experienced solution?