Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super announce car that I am ready to steer 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 infuriating 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. put up to to the dealer.. this get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common hardship in the manner 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 dependence to be re-adjusted? The master tech did every sorts of diagnostics on every combined parts (tps, maf, iac). 0-200 every grow old I tolerate it attain the dealer for diagnostics.. on going problems are truly tally up. I m undecided to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its moreover worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel beast delivered to the engine. Might furthermore be worth cleaning out the idle promptness control motor / valve as these get clogged stirring behind carbon and some brake cleaner washed through helps pardon things off.
This could be a large vacuum leak ,with the MAF aligned it is by yourself measuring the freshen that is getting gone the MAF, for that reason if the intake manifold is sucking in freshen the ventilate to fuel ratio will be certainly out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. next carb cleaner spray spray in the area of the hissing following the engine dispensation and gone you listen the engine stall or rev later there is the leak ,could be a bad vacuum hose bad gasket on the manifold.