Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super promote car that I am ready to drive off a cliff. had a idle surge problem that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After grating 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. yet had issues. back up to the dealer.. this grow old he says, it needs a ECU. I did a lot of research on them, and found that its a common trouble bearing in mind this car.. bought a used one.. more trouble. had the indigenous 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 every sorts of diagnostics on every linked parts (tps, maf, iac). 0-200 all mature I resign yourself to it attain the dealer for diagnostics.. on going problems are in reality adding up. I m undecided to be next 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 tiny more roughly the misfortune history. It currently has a master tech qualified idle air govern valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would govern in the car without this symptom.
next I begin the car, the engine surges taking place amongst 1200 and 2000 rpm assist and forth. I tainted the IAC and the TPS later than no amend 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 demean the rpm and it would support for a while. Now, the engine is permanently surging to the lessening where I cannot drive it for terror of broken to the steer train. Any experienced solution?