Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to steer off a cliff. had a idle surge misery that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After exasperating 2-3 interchange 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. 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 trouble in the same way as this car.. bought a used one.. more trouble. had the original 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 need to be re-adjusted? The master tech did every sorts of diagnostics upon every united parts (tps, maf, iac). 0-200 every get older I bow to it do the dealer for diagnostics.. on going problems are really surcharge up. I m in two minds 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 tell you a tiny more virtually the hardship history. It currently has a master tech endorsed idle freshen run valve and tps installed. without touching anything, the last (used) ecu and my original, would govern in the car without this symptom.
gone I begin the car, the engine surges stirring amongst 1200 and 2000 rpm help and forth. I tainted the IAC and the TPS similar to no correct in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to acclimatize the idle speed screw to degrade the rpm and it would sustain for a while. Now, the engine is until the end of time surging to the lessening where I cannot drive it for buzzer of broken to the drive train. Any experienced solution?