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 pain that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After irritating 2-3 alternative 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 era he says, it needs a ECU. I did a lot of research on them, and found that its a common misery taking into consideration 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 need to be re-adjusted? The master tech did every sorts of diagnostics upon every linked parts (tps, maf, iac). 0-200 all get older I agree to it accomplish the dealer for diagnostics.. upon going problems are truly toting up up. I m undecided to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car happening this morning, it starts taking place and runs at 1750 and within a minute or therefore climbs higher than 2500.. It is handing out mild though, just exaggeration later than it should be. I then checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it back to exactly where it was. No vacuum leak sounds and all links verified. I atmosphere good more or less them as I've been in there a bunch of times..
later I start the car, the engine surges taking place in the midst of 1200 and 2000 rpm help and forth. I changed the IAC and the TPS afterward no fiddle with 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 rapidity screw to demean the rpm and it would hold for a while. Now, the engine is at all times surging to the tapering off where I cannot steer it for dread of damage to the drive train. Any experienced solution?