Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to steer off a cliff. had a idle surge problem that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After grating 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. yet had issues. assist to the dealer.. this get older he says, it needs a ECU. I did a lot of research on them, and found that its a common hardship following 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 dependence to be re-adjusted? The master tech did every sorts of diagnostics on every associated parts (tps, maf, iac). 0-200 every epoch I endure it complete the dealer for diagnostics.. upon going problems are in point of fact calculation up. I m of two minds to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its plus worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a below par pump will all upshot in insufficient fuel mammal delivered to the engine. Might in addition to be worth cleaning out the idle rapidity control motor / valve as these get clogged going on gone carbon and some brake cleaner washed through helps free things off.
like I begin the car, the engine surges stirring in the midst of 1200 and 2000 rpm help and forth. I untouched the IAC and the TPS once no tweak 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 humiliate the rpm and it would sustain for a while. Now, the engine is for ever and a day surging to the reduction where I cannot steer it for fright of broken to the drive train. Any experienced solution?