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 trying 2-3 stand-in 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. help to the dealer.. this time he says, it needs a ECU. I did a lot of research upon them, and found that its a common burden taking into consideration 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 need to be re-adjusted? The master tech did every sorts of diagnostics upon all related parts (tps, maf, iac). 0-200 every get older I endure it pull off the dealer for diagnostics.. on going problems are in reality appendage up. I m hesitant 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 tell you a little more approximately the hardship history. It currently has a master tech ascribed idle freshen run valve and tps installed. without upsetting anything, the last (used) ecu and my original, would rule in the car without this symptom.
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you occurring 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 measure many factors may cause the same symptom(s)