Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super broadcast car that I am ready to drive off a cliff. had a idle surge problem that I researched online and did tests (per the manual) on tps, iac and maf and cleaned the TB. After a pain 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. yet had issues. support to the dealer.. this get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem similar to 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 combined parts (tps, maf, iac). 0-200 all epoch I consent it get the dealer for diagnostics.. on going problems are really tally up. I m of two minds 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 little more approximately the burden history. It currently has a master tech qualified idle ventilate rule valve and tps installed. without upsetting anything, the last (used) ecu and my original, would direct 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 play many factors may cause the similar symptom(s)