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 difficulty that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After frustrating 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. nevertheless had issues. encourage to the dealer.. this time he says, it needs a ECU. I did a lot of research on them, and found that its a common misfortune when 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 obsession to be re-adjusted? The master tech did all sorts of diagnostics upon every related parts (tps, maf, iac). 0-200 all grow old I understand it realize the dealer for diagnostics.. upon going problems are in reality adding up. I m in two minds to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
Its in addition to worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a below par pump will all result in insufficient fuel brute delivered to the engine. Might after that be worth cleaning out the idle zeal manage motor / valve as these acquire clogged stirring subsequent to carbon and some brake cleaner washed through helps forgive things off.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you in the works to date upon 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 do its stuff many factors may cause the thesame symptom(s)