Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to drive 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 interchange 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. put up to 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 later 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 compulsion to be re-adjusted? The master tech did every sorts of diagnostics upon every related parts (tps, maf, iac). 0-200 every era I acknowledge it reach the dealer for diagnostics.. upon going problems are essentially addendum up. I m undecided to be adjacent 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 freshen flow meter and said it was good. behind I unplug it and control the motor, the car runs sharp and at 850ish. I can unaided guess that my new rebuilt ecu has an issue, or the tps needs to be re-adjusted, or somehow my maf has died in the midst of every this. I don't think the tps has that much control in the different of rpm though? I think it unaccompanied adjusts it on the order of 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you happening to date upon all maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms up and is warmed up? oftentimes in engine fake many factors may cause the same symptom(s)