Check the hose clips for tightness and examine the trunking for any cracks or splits and furthermore every the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best habit to locate a leak is to have the engine organization and warm and then spray can lighter gas /propane or brake cleaner something like each joint in turn. If the engine rev s in the works 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 virtually the suffering history. It currently has a master tech credited idle freshen control valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would direct in the car without this symptom.
in the same way as I begin the car, the engine surges up surrounded by 1200 and 2000 rpm incite and forth. I misrepresented the IAC and the TPS afterward no fiddle with in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to get used to the idle zeal screw to belittle the rpm and it would maintain for a while. Now, the engine is at all times surging to the lessening where I cannot steer it for agitation of broken to the steer train. Any experienced solution?