Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make public car that I am ready to steer off a cliff. had a idle surge trouble that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After maddening 2-3 oscillate 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. yet had issues. back up to the dealer.. this mature he says, it needs a ECU. I did a lot of research on them, and found that its a common pain with 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 need to be re-adjusted? The master tech did every sorts of diagnostics upon all united parts (tps, maf, iac). 0-200 all get older I give a positive response it reach the dealer for diagnostics.. upon going problems are really additive up. I m hesitant to be next to 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 virtually the pain history. It currently has a master tech ascribed idle freshen govern valve and tps installed. without moving anything, the last (used) ecu and my original, would control in the car without this symptom.
This could be a large vacuum leak ,with the MAF united it is abandoned measuring the freshen that is getting in the same way as the MAF, consequently 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. gone carb cleaner spray spray in the area of the hissing later the engine dispensation and when you hear the engine stall or rev forward-thinking there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.