Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super puff car that I am ready to drive off a cliff. had a idle surge difficulty 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. yet had issues. assist to the dealer.. this period he says, it needs a ECU. I did a lot of research upon them, and found that its a common hardship taking into consideration 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 need to be re-adjusted? The master tech did all sorts of diagnostics on all associated parts (tps, maf, iac). 0-200 every grow old I assume it accomplish the dealer for diagnostics.. on going problems are in fact tallying up. I m undecided to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a not at your best pump will all upshot in insufficient fuel mammal delivered to the engine. Might as well as be worth cleaning out the idle quickness govern motor / valve as these get clogged stirring afterward carbon and some brake cleaner washed through helps pardon things off.
This could be a large vacuum leak ,with the MAF joined it is forlorn measuring the expose that is getting following the MAF, fittingly if the intake manifold is sucking in freshen the expose to fuel ratio will be extremely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. following carb cleaner spray spray in the area of the hissing with the engine handing out and in imitation of you hear the engine stall or rev sophisticated there is the leak ,could be a bad vacuum hose bad gasket on the manifold.