Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to steer off a cliff. had a idle surge trouble that I researched online and did tests (per the manual) upon tps, iac and maf and cleaned the TB. After infuriating 2-3 substitute 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. back up to the dealer.. this grow old he says, it needs a ECU. I did a lot of research on them, and found that its a common misery following 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 aligned parts (tps, maf, iac). 0-200 every mature I take on it pull off the dealer for diagnostics.. on going problems are in fact add-on up. I m hesitant to lie alongside the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car taking place this morning, it starts occurring and runs at 1750 and within a minute or fittingly climbs exceeding 2500.. It is organization serene though, just pretension superior than it should be. I as well as checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it urge on to exactly where it was. No vacuum leak sounds and all contacts verified. I air fine roughly them as I've been in there a bunch of times..
have you looked into throttle body coking and/or combustion chamber/valve carbon buildup? are you up to date upon every maintenance; spark plugs fuel filter pcv vlave etc? have you performed a visual inspection and listened to engine as it warms occurring and is warmed up? oftentimes in engine put it on many factors may cause the thesame symptom(s)