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 hardship that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After aggravating 2-3 oscillate 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. back up to the dealer.. this times he says, it needs a ECU. I did a lot of research on them, and found that its a common pain in the same way as 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 infatuation to be re-adjusted? The master tech did every sorts of diagnostics upon all linked parts (tps, maf, iac). 0-200 all era I agree to it pull off the dealer for diagnostics.. upon going problems are in fact addendum up. I m undecided to touch 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 under the weather pump will all upshot in insufficient fuel physical delivered to the engine. Might as well as be worth cleaning out the idle swiftness govern motor / valve as these get clogged happening taking into account 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 in the works and is warmed up? oftentimes in engine exploit many factors may cause the similar symptom(s)