Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super broadcast car that I am ready to drive off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After trying 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. nevertheless had issues. assist 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 considering this car.. bought a used one.. more trouble. had the native 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 infatuation to be re-adjusted? The master tech did every sorts of diagnostics upon every related parts (tps, maf, iac). 0-200 all mature I agree to it complete the dealer for diagnostics.. upon going problems are essentially adjunct up. I m in two minds to touch 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 air flow meter and said it was good. taking into account I unplug it and direct the motor, the car runs harsh and at 850ish. I can abandoned guess that my other rebuilt ecu has an issue, or the tps needs to be re-adjusted, or somehow my maf has died in the midst of all this. I don't think the tps has that much control in the oscillate of rpm though? I think it lonely adjusts it regarding 1k..
as soon as I begin the car, the engine surges up amid 1200 and 2000 rpm help and forth. I tainted the IAC and the TPS next no change in symptoms. I have noticed that several Lexus SC's have this thesame issue. Prior to this I would have to adapt the idle enthusiasm screw to degrade the rpm and it would retain for a while. Now, the engine is permanently surging to the tapering off where I cannot steer it for panic of broken to the steer train. Any experienced solution?