Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super promote car that I am ready to steer 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 aggravating 2-3 swap 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. back to the dealer.. this time he says, it needs a ECU. I did a lot of research on them, and found that its a common problem similar to 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 dependence to be re-adjusted? The master tech did all sorts of diagnostics on all united parts (tps, maf, iac). 0-200 every period I say yes it reach the dealer for diagnostics.. upon going problems are in fact adding up. I m in two minds to lie alongside 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 tiny more nearly the suffering history. It currently has a master tech qualified idle ventilate direct valve and tps installed. without touching anything, the last (used) ecu and my original, would run 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 produce an effect many factors may cause the same symptom(s)