Check the hose clips for tightness and inspect the trunking for any cracks or splits and along with every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best quirk to find a leak is to have the engine doling out and warm and subsequently vaporizer lighter gas /propane or brake cleaner around each joint in turn. If the engine rev s going on you ve found your leak.
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me say you a little more more or less the misfortune history. It currently has a master tech ascribed idle ventilate direct valve and tps installed. without disturbing anything, the last (used) ecu and my original, would run in the car without this symptom.
like I start the car, the engine surges occurring together with 1200 and 2000 rpm assist and forth. I tainted the IAC and the TPS when no amend in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to become accustomed the idle readiness screw to demean the rpm and it would support for a while. Now, the engine is for eternity surging to the lessening where I cannot steer it for bell of broken to the steer train. Any experienced solution?