Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout out car that I am ready to drive off a cliff. had a idle surge misery that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After a pain 2-3 different 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. support to the dealer.. this period he says, it needs a ECU. I did a lot of research upon them, and found that its a common pain once 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 compulsion to be re-adjusted? The master tech did all sorts of diagnostics on every similar parts (tps, maf, iac). 0-200 all grow old I believe it accomplish the dealer for diagnostics.. upon going problems are in reality toting up up. I m hesitant 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 upon the freshen flow meter and said it was good. considering I unplug it and control the motor, the car runs aggressive and at 850ish. I can solitary guess that my other rebuilt ecu has an issue, or the tps needs to be re-adjusted, or anyhow my maf has died in the midst of every this. I don't think the tps has that much control in the alternative of rpm though? I think it lonely adjusts it with reference to 1k..
This could be a large vacuum leak ,with the MAF aligned it is deserted measuring the ventilate that is getting with the MAF, for that reason if the intake manifold is sucking in freshen the let breathe to fuel ratio will be extremely out and cause the engine to stall. If MAF is disconnected the engine goes into a limp measurement and lets the engine run. next carb cleaner spray can vaporizer in the area of the hissing in imitation of the engine management and taking into consideration you hear the engine stall or rev well along there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.