Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to steer off a cliff. had a idle surge hardship that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After trying 2-3 vary 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. nevertheless had issues. urge on 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 difficulty subsequent to 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 craving to be re-adjusted? The master tech did all sorts of diagnostics upon all connected parts (tps, maf, iac). 0-200 all times I acknowledge it accomplish the dealer for diagnostics.. on going problems are really accumulation up. I m unsure to adjoin the tps if he had it dialed. Any insight? Thanks in advance. Jason
Might furthermore be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can reach a quick malfunction find if you unplug the meter and rule the engine without it. if the engine condition is the thesame after that chances are the meter or the connection to it is faulty. Its as well as worth cleaning the MAF sensor wires, as they can acquire coated gone dirt over become old which subsequently offsets the reading. Use some admission cleaner or brake cleaner to vaporizer onto the wires to surgically remove the dirt upon no account be adjacent to the wires past all as they are enormously fragile
This could be a large vacuum leak ,with the MAF related it is single-handedly measuring the freshen that is getting afterward the MAF, so if the intake manifold is sucking in ventilate the ventilate to fuel ratio will be very out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. bearing in mind carb cleaner spray spray can in the area of the hissing like the engine organization and taking into consideration you hear the engine stall or rev progressive there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.