Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super puff car that I am ready to steer 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 frustrating 2-3 exchange 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. encourage to the dealer.. this epoch he says, it needs a ECU. I did a lot of research on them, and found that its a common difficulty 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 need to be re-adjusted? The master tech did every sorts of diagnostics on every related parts (tps, maf, iac). 0-200 all times I admit it accomplish the dealer for diagnostics.. on going problems are really tallying up. I m hesitant to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can pull off a fast irregularity find if you unplug the meter and control the engine without it. if the engine condition is the similar subsequently chances are the meter or the association to it is faulty. Its next worth cleaning the MAF sensor wires, as they can get coated when dirt exceeding times which later offsets the reading. Use some open cleaner or brake cleaner to spray onto the wires to remove the dirt upon no account touch the wires subsequently whatever as they are categorically fragile
This could be a large vacuum leak ,with the MAF similar it is and no-one else measuring the air that is getting when the MAF, suitably if the intake manifold is sucking in ventilate the freshen to fuel ratio will be entirely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. with carb cleaner spray vaporizer in the place of the hissing considering the engine direction and bearing in mind you listen the engine stall or rev later there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.