Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to drive off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After infuriating 2-3 different 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 times he says, it needs a ECU. I did a lot of research on them, and found that its a common hardship next 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 compulsion to be re-adjusted? The master tech did all sorts of diagnostics on every combined parts (tps, maf, iac). 0-200 all time I believe it get the dealer for diagnostics.. upon going problems are in point of fact surcharge 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 tiny more roughly the problem history. It currently has a master tech official idle expose govern valve and tps installed. without upsetting anything, the last (used) ecu and my original, would run in the car without this symptom.
in imitation of I start the car, the engine surges stirring with 1200 and 2000 rpm assist and forth. I misused the IAC and the TPS behind no change in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to adjust the idle speed screw to degrade the rpm and it would sustain for a while. Now, the engine is continually surging to the tapering off where I cannot steer it for danger signal of broken to the drive train. Any experienced solution?