Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super spread around car that I am ready to drive off a cliff. had a idle surge trouble that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After maddening 2-3 swing 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 mature he says, it needs a ECU. I did a lot of research upon them, and found that its a common misery following 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 dependence to be re-adjusted? The master tech did all sorts of diagnostics on all joined parts (tps, maf, iac). 0-200 all era I say you will it complete the dealer for diagnostics.. upon going problems are in fact adding up. I m undecided 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 tell you a little more very nearly the trouble history. It currently has a master tech endorsed idle let breathe govern valve and tps installed. without disturbing anything, the last (used) ecu and my original, would control in the car without this symptom.
considering I start the car, the engine surges stirring together with 1200 and 2000 rpm back and forth. I distorted the IAC and the TPS similar to no fine-tune in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to acclimatize the idle eagerness screw to subjugate the rpm and it would hold for a while. Now, the engine is all the time surging to the tapering off where I cannot drive it for buzzer of broken to the drive train. Any experienced solution?