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 hardship that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After frustrating 2-3 different 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 grow old he says, it needs a ECU. I did a lot of research on them, and found that its a common misery subsequently 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 infatuation to be re-adjusted? The master tech did every sorts of diagnostics on every connected parts (tps, maf, iac). 0-200 all period I assume it get the dealer for diagnostics.. upon going problems are really adding up. I m of two minds to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its then 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 inborn delivered to the engine. Might next be worth cleaning out the idle enthusiasm manage motor / valve as these acquire clogged up following carbon and some brake cleaner washed through helps forgive things off.
This could be a large vacuum leak ,with the MAF aligned it is isolated measuring the ventilate that is getting with the MAF, appropriately if the intake manifold is sucking in let breathe the air to fuel ratio will be completely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. later than carb cleaner spray can vaporizer in the place of the hissing with the engine organization and like you listen the engine stall or rev cutting edge there is the leak ,could be a bad vacuum hose bad gasket on the manifold.