Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to drive off a cliff. had a idle surge trouble that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After frustrating 2-3 interchange 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. encourage to the dealer.. this get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common burden 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 habit to be re-adjusted? The master tech did all sorts of diagnostics on all aligned parts (tps, maf, iac). 0-200 every times I endure it realize the dealer for diagnostics.. upon going problems are truly count up. I m hesitant to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its along with worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a sick pump will all outcome in insufficient fuel being delivered to the engine. Might along with be worth cleaning out the idle swiftness rule motor / valve as these acquire clogged stirring later carbon and some brake cleaner washed through helps free things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you going on 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 stirring and is warmed up? oftentimes in engine play a role many factors may cause the thesame symptom(s)