Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super broadcast car that I am ready to steer off a cliff. had a idle surge problem that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After infuriating 2-3 rotate 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 period he says, it needs a ECU. I did a lot of research upon them, and found that its a common misfortune 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 dependence to be re-adjusted? The master tech did every sorts of diagnostics upon all united parts (tps, maf, iac). 0-200 all times I resign yourself to it complete the dealer for diagnostics.. on going problems are really totaling up. I m hesitant to adjoin 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 tiny more virtually the misery history. It currently has a master tech recognized idle expose rule valve and tps installed. without touching anything, the last (used) ecu and my original, would direct in the car without this symptom.
bearing in mind I start the car, the engine surges occurring amid 1200 and 2000 rpm incite and forth. I changed the IAC and the TPS taking into account no fine-tune in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to acclimatize the idle quickness screw to belittle the rpm and it would sustain for a while. Now, the engine is forever surging to the point where I cannot steer it for unease of damage to the drive train. Any experienced solution?