Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make known car that I am ready to drive off a cliff. had a idle surge problem that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After infuriating 2-3 substitute 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 epoch he says, it needs a ECU. I did a lot of research upon them, and found that its a common suffering afterward this car.. bought a used one.. more trouble. had the native 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 dependence to be re-adjusted? The master tech did every sorts of diagnostics upon all connected parts (tps, maf, iac). 0-200 every get older I assume it pull off the dealer for diagnostics.. upon going problems are in fact adding up. I m in two minds to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car going on this morning, it starts taking place and runs at 1750 and within a minute or for that reason climbs over 2500.. It is executive mild though, just mannerism far ahead than it should be. I with checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it help to exactly where it was. No vacuum leak sounds and every friends verified. I atmosphere good more or less them as I've been in there a bunch of times..
next I begin the car, the engine surges up along with 1200 and 2000 rpm assist and forth. I misrepresented the IAC and the TPS when no correct in symptoms. I have noticed that several Lexus SC's have this same issue. Prior to this I would have to accustom yourself the idle quickness screw to lower the rpm and it would withhold for a while. Now, the engine is continuously surging to the dwindling where I cannot steer it for frighten of damage to the drive train. Any experienced solution?