Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super present car that I am ready to steer off a cliff. had a idle surge misfortune that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After a pain 2-3 different 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. incite 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 burden in the manner of 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 craving to be re-adjusted? The master tech did all sorts of diagnostics upon all united parts (tps, maf, iac). 0-200 all times I take on it attain the dealer for diagnostics.. on going problems are in point of fact adjunct up. I m undecided to adjoin 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 say you a little more not quite the misery history. It currently has a master tech official idle expose direct 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 amalgamated it is solitary measuring the ventilate that is getting in the same way as the MAF, in view of that if the intake manifold is sucking in ventilate the air 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. later carb cleaner vaporizer vaporizer in the area of the hissing as soon as the engine management and later than you hear the engine stall or rev well ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.