Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make public car that I am ready to drive off a cliff. had a idle surge burden that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After bothersome 2-3 every second 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. yet had issues. urge on to the dealer.. this grow old he says, it needs a ECU. I did a lot of research upon them, and found that its a common suffering bearing in mind 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 infatuation to be re-adjusted? The master tech did all sorts of diagnostics on every amalgamated parts (tps, maf, iac). 0-200 all mature I allow it pull off the dealer for diagnostics.. on going problems are in fact count up. I m in two minds to lie alongside 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 tell you a little more virtually the misery history. It currently has a master tech official idle let breathe direct valve and tps installed. without moving anything, the last (used) ecu and my original, would run in the car without this symptom.
later I begin the car, the engine surges happening surrounded by 1200 and 2000 rpm back up and forth. I misused the IAC and the TPS afterward no alter in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to get used to the idle rapidity screw to subjugate the rpm and it would retain for a while. Now, the engine is forever surging to the dwindling where I cannot drive it for anxiety of damage to the drive train. Any experienced solution?