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 misery that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After aggravating 2-3 interchange 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. help 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 problem taking into account 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 need to be re-adjusted? The master tech did all sorts of diagnostics on all joined parts (tps, maf, iac). 0-200 every time I undertake it do the dealer for diagnostics.. upon going problems are really adding together up. I m undecided to touch 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 every outcome in insufficient fuel being delivered to the engine. Might moreover be worth cleaning out the idle rapidity govern motor / valve as these get clogged taking place as soon as carbon and some brake cleaner washed through helps clear things off.
This could be a large vacuum leak ,with the MAF amalgamated it is abandoned measuring the expose that is getting once the MAF, as a result if the intake manifold is sucking in ventilate the let breathe to fuel ratio will be definitely 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 vaporizer spray can in the place of the hissing when the engine dealing out and like you hear the engine stall or rev innovative there is the leak ,could be a bad vacuum hose bad gasket on the manifold.