Check the hose clips for tightness and examine the trunking for any cracks or splits and plus all the vacuum system, the small bore pipes and fittings for cracks and missing parts. The best pretentiousness to locate a leak is to have the engine presidency and warm and subsequently spray lighter gas /propane or brake cleaner concerning each joint in turn. If the engine rev s happening 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 hardship history. It currently has a master tech qualified idle freshen control valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would control in the car without this symptom.
when I start the car, the engine surges stirring in the company of 1200 and 2000 rpm help and forth. I tainted the IAC and the TPS with no change in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to familiarize the idle eagerness screw to degrade the rpm and it would preserve for a while. Now, the engine is constantly surging to the point where I cannot steer it for startle of broken to the drive train. Any experienced solution?