Doug - Would value your confirmation on the added problems of RV ownerships due to the rapid number of smog related regulations rolled out? From about say 2005 and on smog regulations, and thus the need of the engine manufactures to design and certify (Many times on very short cycles.) new equipment to meet the new regulations.) (And note: This is not intended as a anti smog post, it's about the frequency of the changes and how they were rolled out...).
Many systems and components in RV's, but I've watched forums traffic in the engine related areas problems grow due to the teething pains of new smog levels equipments maturing cycle.
TIA for your perception,
Smitty