Check the hose clips for tightness and inspect the trunking for any cracks or splits and with all the vacuum system, the little bore pipes and fittings for cracks and missing parts. The best quirk to locate a leak is to have the engine doling out and hot and after that spray can lighter gas /propane or brake cleaner regarding each joint in turn. If the engine rev s occurring 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 tell you a tiny more approximately the burden history. It currently has a master tech attributed idle air govern valve and tps installed. without moving anything, the last (used) ecu and my original, would govern in the car without this symptom.
similar to I begin the car, the engine surges taking place amongst 1200 and 2000 rpm urge on and forth. I misused the IAC and the TPS once no alter in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to accustom yourself the idle promptness screw to lower the rpm and it would support for a while. Now, the engine is constantly surging to the lessening where I cannot steer it for unease of broken to the steer train. Any experienced solution?