Hi, this car is kicking everyone s ass.. 92 lexus sc400. 128k. Super publicize car that I am ready to drive off a cliff. had a idle surge suffering that I researched online and did tests (per the manual) on 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 get older he says, it needs a ECU. I did a lot of research upon them, and found that its a common problem taking into account this car.. bought a used one.. more trouble. had the indigenous 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 craving to be re-adjusted? The master tech did all sorts of diagnostics on every connected parts (tps, maf, iac). 0-200 every times I understand it get the dealer for diagnostics.. upon going problems are in fact surcharge up. I m hesitant to be adjacent to the tps if he had it dialed. Any insight? Thanks in advance. Jason
I started the car up this morning, it starts occurring and runs at 1750 and within a minute or thus climbs higher than 2500.. It is running smooth though, just pretentiousness unconventional than it should be. I plus checked the throttle screw plate/return screw, purposefully turned it out and nothing changed. put it support to exactly where it was. No vacuum leak sounds and every friends verified. I vibes fine not quite 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 stirring and is warmed up? oftentimes in engine produce a result many factors may cause the similar symptom(s)