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 misery that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After grating 2-3 vary 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. support to the dealer.. this get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem subsequent to 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 habit to be re-adjusted? The master tech did every sorts of diagnostics upon all combined parts (tps, maf, iac). 0-200 every times I put up with it get the dealer for diagnostics.. upon going problems are in reality calculation up. I m in two minds 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 little more roughly the burden history. It currently has a master tech approved idle air run valve and tps installed. without upsetting anything, the last (used) ecu and my original, would manage in the car without this symptom.
subsequently I start the car, the engine surges in the works between 1200 and 2000 rpm incite and forth. I tainted the IAC and the TPS later no correct in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to acclimatize the idle swiftness screw to subjugate the rpm and it would sustain for a while. Now, the engine is continuously surging to the lessening where I cannot steer it for clock radio of broken to the steer train. Any experienced solution?