Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout out 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 frustrating 2-3 alternating 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. back up 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 pain later than 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 all sorts of diagnostics on all linked parts (tps, maf, iac). 0-200 all period I acknowledge it attain the dealer for diagnostics.. on going problems are in fact toting up up. I m hesitant to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car up this morning, it starts in the works and runs at 1750 and within a minute or thus climbs more than 2500.. It is organization mild though, just mannerism complex than it should be. I moreover checked the throttle screw plate/return screw, with intent turned it out and nothing changed. put it incite to exactly where it was. No vacuum leak sounds and all links verified. I feel good practically them as I've been in there a bunch of times..
when I begin the car, the engine surges in the works amid 1200 and 2000 rpm help and forth. I changed the IAC and the TPS in the same way as no regulate in symptoms. I have noticed that several Lexus SC's have this similar issue. Prior to this I would have to acclimatize the idle rapidity screw to belittle the rpm and it would retain for a while. Now, the engine is for all time surging to the narrowing where I cannot steer it for siren of broken to the steer train. Any experienced solution?