Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super market car that I am ready to steer off a cliff. had a idle surge misfortune that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After maddening 2-3 different 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. still had issues. back up to the dealer.. this period he says, it needs a ECU. I did a lot of research upon them, and found that its a common misfortune past this car.. bought a used one.. more trouble. had the indigenous 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 on all connected parts (tps, maf, iac). 0-200 all period I allow it complete the dealer for diagnostics.. on going problems are in point of fact addendum up. I m unsure to be next to the tps if he had it dialed. Any insight? Thanks in advance. Jason
Thanks for your response. I just checked what you mentioned, that I hadn't already checked, except fuel pressure.Let me say you a tiny more about the trouble history. It currently has a master tech attributed idle ventilate manage valve and tps installed. without touching anything, the last (used) ecu and my original, would manage in the car without this symptom.
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 going on and is warmed up? oftentimes in engine do something many factors may cause the same symptom(s)