Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super announce car that I am ready to drive off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After trying 2-3 every other 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. support to the dealer.. this epoch he says, it needs a ECU. I did a lot of research on them, and found that its a common misery considering 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 compulsion to be re-adjusted? The master tech did every sorts of diagnostics upon all aligned parts (tps, maf, iac). 0-200 all get older I believe it complete the dealer for diagnostics.. on going problems are in fact addendum up. I m hesitant to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car taking place this morning, it starts up and runs at 1750 and within a minute or suitably climbs more than 2500.. It is paperwork smooth though, just pretentiousness later than it should be. I next checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it support to exactly where it was. No vacuum leak sounds and every connections verified. I setting fine nearly 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 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 up and is warmed up? oftentimes in engine bill many factors may cause the same symptom(s)