G'day, yes been to dealer. Not enough of a miss to throw a code, but I can feel it it idle. Have been on a drive with laptop plugged in and he can see random misfires across some cylinders. Its not burning a lot of oil, but the plugs are fowled. They just keep cleaning them. I'm in Australia so the local right hand drive conversion crowd who warrant them are the ones asking to wait till 10kms i.e. kicking it down the road. I walked into it eyes open. My last Silverado (06) was converted locally too and had zero issues with it. Its very frustrating.