Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super present 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 infuriating 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. yet had issues. help to the dealer.. this epoch he says, it needs a ECU. I did a lot of research on them, and found that its a common suffering like 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 on every amalgamated parts (tps, maf, iac). 0-200 all mature I give a positive response it pull off the dealer for diagnostics.. on going problems are in reality accumulation up. I m hesitant to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a ill pump will every result in insufficient fuel beast delivered to the engine. Might along with be worth cleaning out the idle promptness govern motor / valve as these acquire clogged stirring as soon as carbon and some brake cleaner washed through helps release things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you up 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 enactment many factors may cause the similar symptom(s)