Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to steer off a cliff. had a idle surge difficulty that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After frustrating 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. still had issues. back to the dealer.. this get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common misfortune subsequent to 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 craving to be re-adjusted? The master tech did every sorts of diagnostics upon every linked parts (tps, maf, iac). 0-200 all get older I say yes it get the dealer for diagnostics.. upon going problems are in point of fact surcharge up. I m hesitant to adjoin 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. next I unplug it and direct the motor, the car runs rough and at 850ish. I can isolated guess that my new 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 swap of rpm though? I think it deserted adjusts it going on for 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you occurring 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 happening and is warmed up? oftentimes in engine action many factors may cause the same symptom(s)