Check the hose clips for tightness and inspect the trunking for any cracks or splits and plus every the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best habit to find a leak is to have the engine management and hot and next spray can lighter gas /propane or brake cleaner in the region of 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 tiny more not quite the suffering history. It currently has a master tech attributed idle air run valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would run in the car without this symptom.
past I start the car, the engine surges happening along with 1200 and 2000 rpm urge on and forth. I changed the IAC and the TPS next no correct in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to familiarize the idle promptness screw to demean the rpm and it would support for a while. Now, the engine is forever surging to the point where I cannot steer it for terrify of damage to the steer train. Any experienced solution?