I have the same problem and it has gotten worse. It is a fuel delivery issue for sure. I have a clear fuel filter and when the motor starts to shut down the filter is empty and bubbling.....What are your thoughts?
I suggest you look back at my post in this thread on 8-6-2013 (9:45pm). My issue turned out to be vapor lock in the fuel line and your description of “bubbling gas” in the filter makes me think yours could be same. Mine began occurring because I’d shortened the fuel line, getting it closer to the hot engine, and moved the remaining fuel line heat shield to the wrong location. A longer fuel line and renewed heat shield completely solved it. Been great ever since. Hopefully your fix will be as simple.