I had similar problems years ago.... intermittent rough running, loss of power, and engine all but stopping, etc. I put it in several shops for extended periods of time with them driving it daily.
Finally changed out the O2 sensors and the problem went away. I'm not sure if your coach has O2 sensors on the exhaust but that's another almost cheap part to replace.
Enjoy Life! It's later than you think. Life changes in a second. There isn't enough time for cheap booze and cheap cigars.