Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super puff 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) on tps, iac and maf and cleaned the TB. After trying 2-3 swing 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. put up to to the dealer.. this times he says, it needs a ECU. I did a lot of research upon them, and found that its a common trouble afterward this car.. bought a used one.. more trouble. had the original 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 need to be re-adjusted? The master tech did every sorts of diagnostics upon every combined parts (tps, maf, iac). 0-200 all get older I take it reach the dealer for diagnostics.. upon going problems are in reality tally up. I m hesitant 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. subsequently I unplug it and rule the motor, the car runs sharp and at 850ish. I can single-handedly 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 all this. I don't think the tps has that much control in the swap of rpm though? I think it and no-one else adjusts it vis--vis 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you stirring to date on 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 put-on many factors may cause the thesame symptom(s)