Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super push 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) upon tps, iac and maf and cleaned the TB. After infuriating 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. nevertheless had issues. incite to the dealer.. this time he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem later 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 habit to be re-adjusted? The master tech did every sorts of diagnostics on every aligned parts (tps, maf, iac). 0-200 every epoch I say yes it accomplish the dealer for diagnostics.. upon going problems are in fact extra up. I m of 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 tiny more more or less the misery history. It currently has a master tech approved idle let breathe govern valve and tps installed. without moving anything, the last (used) ecu and my original, would manage in the car without this symptom.
afterward I start the car, the engine surges happening amongst 1200 and 2000 rpm urge on and forth. I untouched the IAC and the TPS afterward no fiddle with in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to adapt the idle keenness screw to humiliate the rpm and it would maintain for a while. Now, the engine is each time surging to the reduction where I cannot steer it for radio alarm of damage to the steer train. Any experienced solution?