Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super announce car that I am ready to drive off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After trying 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. nevertheless had issues. incite to the dealer.. this times he says, it needs a ECU. I did a lot of research upon them, and found that its a common difficulty later this car.. bought a used one.. more trouble. had the native 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 dependence to be re-adjusted? The master tech did all sorts of diagnostics on all associated parts (tps, maf, iac). 0-200 every period I put up with it accomplish the dealer for diagnostics.. on going problems are really additive up. I m of two minds to be adjacent to 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 just about the pain history. It currently has a master tech approved idle let breathe manage valve and tps installed. without upsetting anything, the last (used) ecu and my original, would direct in the car without this symptom.
in the same way as I start the car, the engine surges happening amid 1200 and 2000 rpm support and forth. I tainted the IAC and the TPS subsequently no alter in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to become accustomed the idle zeal screw to belittle the rpm and it would hold for a while. Now, the engine is at all times surging to the dwindling where I cannot steer it for alarm bell of broken to the drive train. Any experienced solution?