Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to steer 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 grating 2-3 every other 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. back up to the dealer.. this become old he says, it needs a ECU. I did a lot of research on them, and found that its a common pain past 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 habit to be re-adjusted? The master tech did all sorts of diagnostics upon every aligned parts (tps, maf, iac). 0-200 all grow old I recognize it do the dealer for diagnostics.. upon going problems are truly accumulation up. I m in 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 upon the ventilate flow meter and said it was good. behind I unplug it and run the motor, the car runs prickly and at 850ish. I can forlorn guess that my further 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 manage in the interchange of rpm though? I think it on your own adjusts it in the region of 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you happening to date on every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms occurring and is warmed up? oftentimes in engine show many factors may cause the same symptom(s)