Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout out car that I am ready to steer off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After a pain 2-3 vary 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. help 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 burden in the manner of this car.. bought a used one.. more trouble. had the indigenous 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 on all similar parts (tps, maf, iac). 0-200 all time I acknowledge it complete the dealer for diagnostics.. upon going problems are essentially supplement up. I m in two minds 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 tell you a little more practically the problem history. It currently has a master tech approved idle air control valve and tps installed. without touching 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 partnered it is by yourself measuring the expose that is getting once the MAF, suitably if the intake manifold is sucking in air the expose 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. subsequent to carb cleaner spray can spray in the area of the hissing subsequently the engine direction and considering you hear the engine stall or rev highly developed there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.