Check the hose clips for tightness and examine the trunking for any cracks or splits and after that all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best mannerism to find a leak is to have the engine presidency and hot and later vaporizer lighter gas /propane or brake cleaner with reference to each joint in turn. If the engine rev s up you ve found your leak.
I started the car happening this morning, it starts taking place and runs at 1750 and within a minute or in view of that climbs over 2500.. It is paperwork smooth though, just artifice cutting edge than it should be. I as well as checked the throttle screw plate/return screw, purposefully turned it out and nothing changed. put it incite to exactly where it was. No vacuum leak sounds and every friends verified. I character fine very nearly them as I've been in there a bunch of times..
later I start the car, the engine surges happening amongst 1200 and 2000 rpm urge on and forth. I untouched the IAC and the TPS as soon as no change in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to familiarize the idle promptness screw to belittle the rpm and it would preserve for a while. Now, the engine is until the end of time surging to the dwindling where I cannot drive it for fear of damage to the steer train. Any experienced solution?