A 2012 model with about 1200 hours on it started running rough, missing a bit after start up at idle a few weeks ago and it has progressively gotten worse. After warming up for 5-10 minutes at idle it would mostly smooth out and then when I went out and operated at running speeds, it would run fine and then idle fine for the rest of the trip. Over the last few weeks it has progressively gotten more rough and takes longer to warm the rough out and it is now missing a bit at idle when I slow down between runs.
When I start the engine cold, it starts normally and idles pretty smoothly at first but when it slows to low idle after the initial ten or so seconds of fast idle, the missing and shuddering begin.
As a bit of background, Initially, out of the box, this engine would not start on the first attempt, this was the result of faulty ECU programming which I replaced under warranty from the dealer in Juneau. Immediately after changing the ECU the engine started right up as it should, but for the first time it would shudder(run rough) for a few seconds at a time during the warm up period and on occasion after shutting down to refuel and then restarting warm. It never lasted long and never got worse but this never happened with the original ECU.
So far I have changed the plugs, swapped a coil with my other engine on cylinder 6 as the plug in that hole looked a little darker around the rim than the others, also replaced my 02 sensor, no change in symptoms so I am looking for the next item to try. Sensors,filters, ECU??? Any help would be appreciated.
When I start the engine cold, it starts normally and idles pretty smoothly at first but when it slows to low idle after the initial ten or so seconds of fast idle, the missing and shuddering begin.
As a bit of background, Initially, out of the box, this engine would not start on the first attempt, this was the result of faulty ECU programming which I replaced under warranty from the dealer in Juneau. Immediately after changing the ECU the engine started right up as it should, but for the first time it would shudder(run rough) for a few seconds at a time during the warm up period and on occasion after shutting down to refuel and then restarting warm. It never lasted long and never got worse but this never happened with the original ECU.
So far I have changed the plugs, swapped a coil with my other engine on cylinder 6 as the plug in that hole looked a little darker around the rim than the others, also replaced my 02 sensor, no change in symptoms so I am looking for the next item to try. Sensors,filters, ECU??? Any help would be appreciated.