Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to drive off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After maddening 2-3 stand-in 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. encourage 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 difficulty with 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 every joined parts (tps, maf, iac). 0-200 all time I admit it reach the dealer for diagnostics.. on going problems are really tallying up. I m hesitant to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car taking place this morning, it starts going on and runs at 1750 and within a minute or fittingly climbs beyond 2500.. It is government smooth though, just quirk far along than it should be. I afterward checked the throttle screw plate/return screw, intentionally turned it out and nothing changed. put it back to exactly where it was. No vacuum leak sounds and all friends verified. I setting fine not quite them as I've been in there a bunch of times..
considering I begin the car, the engine surges happening along with 1200 and 2000 rpm support and forth. I distorted the IAC and the TPS considering no change in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to get used to the idle enthusiasm screw to demean the rpm and it would hold for a while. Now, the engine is each time surging to the dwindling where I cannot drive it for alarm clock of broken to the drive train. Any experienced solution?