Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super push car that I am ready to drive 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 frustrating 2-3 alternative 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. nevertheless had issues. urge on 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 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 every partnered parts (tps, maf, iac). 0-200 all times I endure it accomplish the dealer for diagnostics.. on going problems are essentially add-on up. I m in two minds to touch the tps if he had it dialed. Any insight? Thanks in advance. Jason
I did re-check them tho. The master tech did extensive tests on the freshen flow meter and said it was good. similar to I unplug it and control the motor, the car runs rough and at 850ish. I can on your own guess that my extra rebuilt ecu has an issue, or the tps needs to be re-adjusted, or someway my maf has died in the midst of every this. I don't think the tps has that much run in the swing of rpm though? I think it forlorn adjusts it nearly 1k..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you going on 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 in the works and is warmed up? oftentimes in engine play a part many factors may cause the same symptom(s)