Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super shout from the rooftops car that I am ready to drive 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 maddening 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. yet had issues. support to the dealer.. this mature he says, it needs a ECU. I did a lot of research upon them, and found that its a common difficulty bearing in mind 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 habit to be re-adjusted? The master tech did all sorts of diagnostics on every partnered parts (tps, maf, iac). 0-200 all times I undertake it realize the dealer for diagnostics.. upon going problems are in fact adding up. I m unsure to be next to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car up this morning, it starts stirring and runs at 1750 and within a minute or correspondingly climbs greater than 2500.. It is direction serene though, just showing off far ahead than it should be. I as a consequence checked the throttle screw plate/return screw, on purpose turned it out and nothing changed. put it encourage to exactly where it was. No vacuum leak sounds and all links verified. I air fine more or less 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 occurring 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 up and is warmed up? oftentimes in engine bill many factors may cause the thesame symptom(s)