Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to steer off a cliff. had a idle surge pain that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After irritating 2-3 alternative used IAC s, I took it to the master tech at lexus. He said it was the IAC valve. He tried my used ones.. and finally a rebuilt one. still had issues. back up to the dealer.. this time he says, it needs a ECU. I did a lot of research upon them, and found that its a common difficulty once this car.. bought a used one.. more trouble. had the indigenous one rebuilt by a specialist.. and that s where I am at now.. Put it in tonight and the car idles at 2k rpm. Does the TPS craving to be re-adjusted? The master tech did every sorts of diagnostics on all connected parts (tps, maf, iac). 0-200 every get older I take on it realize the dealer for diagnostics.. upon going problems are truly toting up up. I m unsure to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
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 nearly the pain history. It currently has a master tech official idle air run valve and tps installed. without distressing anything, the last (used) ecu and my original, would manage in the car without this symptom.
afterward I begin the car, the engine surges stirring with 1200 and 2000 rpm support and forth. I distorted the IAC and the TPS subsequently no modify in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to familiarize the idle quickness screw to humiliate the rpm and it would hold for a while. Now, the engine is permanently surging to the reduction where I cannot steer it for distress of broken to the steer train. Any experienced solution?