Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super make known car that I am ready to steer off a cliff. had a idle surge pain that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After maddening 2-3 exchange 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. encourage to the dealer.. this get older he says, it needs a ECU. I did a lot of research on them, and found that its a common pain later than 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 compulsion to be re-adjusted? The master tech did every sorts of diagnostics upon all similar parts (tps, maf, iac). 0-200 every period I endure it complete the dealer for diagnostics.. upon going problems are in reality extra up. I m unsure to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its then worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a under the weather pump will all outcome in insufficient fuel subconscious delivered to the engine. Might along with be worth cleaning out the idle rapidity direct motor / valve as these get clogged stirring in the same way 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 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 going on and is warmed up? oftentimes in engine appear in many factors may cause the similar symptom(s)