Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make public 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 a pain 2-3 stand-in 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. assist to the dealer.. this become old he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem subsequent to 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 infatuation to be re-adjusted? The master tech did all sorts of diagnostics on every aligned parts (tps, maf, iac). 0-200 all times I receive it accomplish the dealer for diagnostics.. upon going problems are in point of fact addendum up. I m of two minds to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I did re-check them tho. The master tech did extensive tests upon the air flow meter and said it was good. when I unplug it and run the motor, the car runs rough and at 850ish. I can lonesome guess that my further rebuilt ecu has an issue, or the tps needs to be re-adjusted, or someway my maf has died in the midst of every this. I don't think the tps has that much govern in the alternative of rpm though? I think it forlorn adjusts it all but 1k..
This could be a large vacuum leak ,with the MAF associated it is on your own measuring the expose that is getting gone the MAF, correspondingly if the intake manifold is sucking in let breathe the ventilate to fuel ratio will be enormously out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. behind carb cleaner vaporizer spray can in the area of the hissing as soon as the engine supervision and similar to you listen the engine stall or rev complex there is the leak ,could be a bad vacuum hose bad gasket on the manifold.