Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super puff car that I am ready to drive off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After trying 2-3 every other 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. still had issues. put up to to the dealer.. this period he says, it needs a ECU. I did a lot of research upon them, and found that its a common pain behind this car.. bought a used one.. more trouble. had the original 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 upon every linked parts (tps, maf, iac). 0-200 every era I receive it pull off the dealer for diagnostics.. on going problems are in point of fact extra up. I m in two minds to be adjacent to 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 on the let breathe flow meter and said it was good. when I unplug it and control the motor, the car runs harsh and at 850ish. I can isolated guess that my extra rebuilt ecu has an issue, or the tps needs to be re-adjusted, or anyhow my maf has died in the midst of every this. I don't think the tps has that much rule in the oscillate of rpm though? I think it isolated adjusts it approximately 1k..
This could be a large vacuum leak ,with the MAF partnered it is and no-one else measuring the expose that is getting afterward the MAF, correspondingly if the intake manifold is sucking in air 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. later than carb cleaner spray spray can in the area of the hissing once the engine government and considering you listen the engine stall or rev progressive there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.