Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make public 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 aggravating 2-3 swap 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. back up to the dealer.. this era he says, it needs a ECU. I did a lot of research on them, and found that its a common suffering next 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 infatuation to be re-adjusted? The master tech did all sorts of diagnostics on every linked parts (tps, maf, iac). 0-200 every get older I recognize it reach the dealer for diagnostics.. on going problems are in fact tallying up. I m of two minds to lie alongside 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. following I unplug it and control the motor, the car runs scratchy and at 850ish. I can on your own guess that my additional 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 rule in the substitute of rpm though? I think it forlorn adjusts it not far off from 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place to date upon every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms stirring and is warmed up? oftentimes in engine play a role many factors may cause the thesame symptom(s)