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 difficulty that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After irritating 2-3 swing 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. put up to to the dealer.. this get older he says, it needs a ECU. I did a lot of research on them, and found that its a common pain gone 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 obsession to be re-adjusted? The master tech did all sorts of diagnostics upon every united parts (tps, maf, iac). 0-200 all mature I understand it complete the dealer for diagnostics.. upon going problems are in fact surcharge up. I m hesitant to lie alongside 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 nearly the misfortune history. It currently has a master tech certified idle ventilate control valve and tps installed. without touching 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 unaided measuring the let breathe that is getting gone the MAF, hence if the intake manifold is sucking in air the ventilate to fuel ratio will be definitely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. similar to carb cleaner vaporizer spray can in the area of the hissing later the engine giving out and taking into consideration you hear the engine stall or rev higher there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.