Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout out car that I am ready to drive 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 aggravating 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. nevertheless had issues. help to the dealer.. this become old he says, it needs a ECU. I did a lot of research on them, and found that its a common pain similar to 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 obsession to be re-adjusted? The master tech did all sorts of diagnostics upon all amalgamated parts (tps, maf, iac). 0-200 every times I acknowledge it realize the dealer for diagnostics.. on going problems are essentially count up. I m unsure to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car occurring this morning, it starts happening and runs at 1750 and within a minute or in view of that climbs on top of 2500.. It is government smooth though, just quirk far ahead than it should be. I as a consequence checked the throttle screw plate/return screw, intentionally turned it out and nothing changed. put it assist to exactly where it was. No vacuum leak sounds and every contacts verified. I tone fine just about them as I've been in there a bunch of times..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you taking place 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 occurring and is warmed up? oftentimes in engine function many factors may cause the similar symptom(s)