Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super push car that I am ready to steer 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 infuriating 2-3 every second 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. incite to the dealer.. this era he says, it needs a ECU. I did a lot of research on them, and found that its a common trouble taking into consideration this car.. bought a used one.. more trouble. had the original 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 every sorts of diagnostics on every partnered parts (tps, maf, iac). 0-200 every era I acknowledge it get the dealer for diagnostics.. upon going problems are essentially adding up. I m of two minds to adjoin 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 more or less the problem history. It currently has a master tech approved idle ventilate manage valve and tps installed. without heartwarming anything, the last (used) ecu and my original, would govern 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 every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms taking place and is warmed up? oftentimes in engine function many factors may cause the thesame symptom(s)