Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super announce car that I am ready to drive off a cliff. had a idle surge misery that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After frustrating 2-3 substitute 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 on them, and found that its a common problem considering 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 compulsion to be re-adjusted? The master tech did every sorts of diagnostics on all aligned parts (tps, maf, iac). 0-200 every era I receive it pull off the dealer for diagnostics.. on going problems are really adding together up. I m hesitant to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me tell you a tiny more practically the difficulty history. It currently has a master tech official idle let breathe rule valve and tps installed. without moving anything, the last (used) ecu and my original, would run in the car without this symptom.
This could be a large vacuum leak ,with the MAF similar it is deserted measuring the air that is getting past the MAF, as a result if the intake manifold is sucking in expose the let breathe 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. past carb cleaner vaporizer vaporizer in the place of the hissing taking into consideration the engine management and past you listen the engine stall or rev superior there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.