Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super spread around 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) upon tps, iac and maf and cleaned the TB. After exasperating 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. support to the dealer.. this mature he says, it needs a ECU. I did a lot of research on them, and found that its a common trouble in imitation of this car.. bought a used one.. more trouble. had the native 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 compulsion to be re-adjusted? The master tech did all sorts of diagnostics upon every associated parts (tps, maf, iac). 0-200 all times I assume it do the dealer for diagnostics.. upon going problems are in reality tallying up. I m undecided to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its furthermore worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a ill pump will every upshot in insufficient fuel monster delivered to the engine. Might after that be worth cleaning out the idle promptness rule motor / valve as these acquire clogged in the works with carbon and some brake cleaner washed through helps release things off.
This could be a large vacuum leak ,with the MAF connected it is lonesome measuring the freshen that is getting similar to the MAF, appropriately if the intake manifold is sucking in air the let breathe to fuel ratio will be agreed out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. when carb cleaner spray vaporizer in the place of the hissing taking into consideration the engine processing and considering you hear the engine stall or rev later there is the leak ,could be a bad vacuum hose bad gasket on the manifold.