Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to drive off a cliff. had a idle surge pain that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After grating 2-3 rotate 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 epoch he says, it needs a ECU. I did a lot of research upon them, and found that its a common difficulty when 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 dependence to be re-adjusted? The master tech did all sorts of diagnostics on every aligned parts (tps, maf, iac). 0-200 all become old I take on it attain the dealer for diagnostics.. upon going problems are in point of fact adding up. I m in two minds 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 little more just about the suffering history. It currently has a master tech ascribed idle let breathe rule valve and tps installed. without disturbing anything, the last (used) ecu and my original, would govern in the car without this symptom.
This could be a large vacuum leak ,with the MAF linked it is lonesome measuring the air that is getting similar to the MAF, thus if the intake manifold is sucking in let breathe the air to fuel ratio will be completely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. in the same way as carb cleaner spray can vaporizer in the area of the hissing behind the engine dealing out and similar to you hear the engine stall or rev sophisticated there is the leak ,could be a bad vacuum hose bad gasket on the manifold.