Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super spread around car that I am ready to steer 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 exasperating 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 era he says, it needs a ECU. I did a lot of research upon them, and found that its a common misery when 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 all sorts of diagnostics upon every associated parts (tps, maf, iac). 0-200 all become old I receive it get the dealer for diagnostics.. on going problems are truly appendage up. I m of two minds to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
Might then be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can get a quick fault locate if you unplug the meter and run the engine without it. if the engine condition is the same next chances are the meter or the association to it is faulty. Its also worth cleaning the MAF sensor wires, as they can get coated later dirt exceeding period which after that offsets the reading. Use some admittance cleaner or brake cleaner to vaporizer onto the wires to remove the dirt upon no account adjoin the wires next whatever as they are utterly fragile
This could be a large vacuum leak ,with the MAF similar it is forlorn measuring the freshen that is getting in imitation of the MAF, hence if the intake manifold is sucking in let breathe the ventilate 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. similar to carb cleaner spray can spray in the area of the hissing once the engine processing and considering you hear the engine stall or rev far ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.