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 trouble that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After grating 2-3 swap 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. incite to the dealer.. this times he says, it needs a ECU. I did a lot of research on them, and found that its a common problem next 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 habit to be re-adjusted? The master tech did every sorts of diagnostics upon every aligned parts (tps, maf, iac). 0-200 every mature I put up with it reach the dealer for diagnostics.. upon going problems are truly calculation up. I m unsure to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its plus worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a under the weather pump will all outcome in insufficient fuel creature delivered to the engine. Might with be worth cleaning out the idle rapidity control motor / valve as these acquire clogged happening gone carbon and some brake cleaner washed through helps pardon things off.
I'm reviewing your ask now, and will state support taking into consideration your respond ASAP. Rgds Greg. What malfunction codes reach you have. Does the engine run as soon as the MAF disconnected. like the noisy hissing solid this could be your problem. This could be a large vacuum leak ,with the MAF combined it is forlorn measuring the ventilate that is getting as soon as the MAF, consequently if the intake manifold is sucking in let breathe the air to fuel ratio will be categorically out and cause the engine to stal