Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make public car that I am ready to drive 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 aggravating 2-3 substitute 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. urge on to the dealer.. this time he says, it needs a ECU. I did a lot of research on them, and found that its a common misfortune 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 all sorts of diagnostics upon all aligned parts (tps, maf, iac). 0-200 every times I consent it realize the dealer for diagnostics.. upon going problems are truly extra up. I m undecided 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. subsequent to I unplug it and control the motor, the car runs rasping and at 850ish. I can lonely guess that my extra rebuilt ecu has an issue, or the tps needs to be re-adjusted, or anyhow my maf has died in the midst of all this. I don't think the tps has that much manage in the different of rpm though? I think it and no-one else adjusts it as regards 1k..
This could be a large vacuum leak ,with the MAF connected it is unaccompanied measuring the air that is getting afterward the MAF, correspondingly if the intake manifold is sucking in let breathe the air to fuel ratio will be categorically 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 manner of carb cleaner spray vaporizer in the area of the hissing past the engine executive and behind you listen the engine stall or rev well ahead there is the leak ,could be a bad vacuum hose bad gasket upon the manifold.