Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super broadcast car that I am ready to steer off a cliff. had a idle surge burden that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After bothersome 2-3 alternating 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. help to the dealer.. this time he says, it needs a ECU. I did a lot of research upon them, and found that its a common hardship 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 craving to be re-adjusted? The master tech did every sorts of diagnostics on all aligned parts (tps, maf, iac). 0-200 all mature I acknowledge it reach the dealer for diagnostics.. upon going problems are essentially adding up. I m of two minds to be next to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I did re-check them tho. The master tech did extensive tests on the let breathe flow meter and said it was good. in imitation of I unplug it and manage the motor, the car runs rasping and at 850ish. I can lonesome guess that my further rebuilt ecu has an issue, or the tps needs to be re-adjusted, or someway my maf has died in the midst of every this. I don't think the tps has that much manage in the rotate of rpm though? I think it unaided adjusts it approximately 1k..
This could be a large vacuum leak ,with the MAF amalgamated it is and no-one else measuring the expose that is getting with the MAF, consequently if the intake manifold is sucking in expose the air to fuel ratio will be totally out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. with carb cleaner spray can spray can in the area of the hissing in imitation of the engine dealing out and afterward you hear the engine stall or rev highly developed there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.