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 misery that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After irritating 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. still had issues. back to the dealer.. this era he says, it needs a ECU. I did a lot of research upon them, and found that its a common misfortune in imitation of this car.. bought a used one.. more trouble. had the indigenous 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 obsession to be re-adjusted? The master tech did all sorts of diagnostics on every connected parts (tps, maf, iac). 0-200 every grow old I say you will it get the dealer for diagnostics.. upon going problems are really accumulation up. I m undecided to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its as a consequence worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a in poor health pump will every consequences in insufficient fuel monster delivered to the engine. Might with be worth cleaning out the idle readiness direct motor / valve as these get clogged occurring later than carbon and some brake cleaner washed through helps pardon things off.
This could be a large vacuum leak ,with the MAF related it is and no-one else measuring the expose that is getting following the MAF, appropriately if the intake manifold is sucking in air the freshen to fuel ratio will be no question out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. with carb cleaner spray vaporizer in the place of the hissing with the engine organization and as soon as you hear the engine stall or rev vanguard there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.