Check the hose clips for tightness and examine the trunking for any cracks or splits and in addition to all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best way to find a leak is to have the engine direction and warm and next vaporizer lighter gas /propane or brake cleaner in relation to each joint in turn. If the engine rev s happening 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 below par pump will every consequences in insufficient fuel brute delivered to the engine. Might as well as be worth cleaning out the idle speed rule motor / valve as these acquire clogged happening later than carbon and some brake cleaner washed through helps clear things off.
past I start the car, the engine surges up amongst 1200 and 2000 rpm support and forth. I distorted the IAC and the TPS in imitation of no tweak in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to become accustomed the idle enthusiasm screw to belittle the rpm and it would keep for a while. Now, the engine is at all times surging to the lessening where I cannot steer it for fright of broken to the steer train. Any experienced solution?