Since we live in CA, we are probably the most anal on passing emissions testing. One thing I learned with my gas chassis under a 35' motorhome: With 30+ feet of exhaust pipe, it takes a while for all the mufflers, cat, and pipes to warm up to operating temp. I failed one test once because of it. So, the next time, the guy told me to drive it on the open road for about 30 min. before he checked it so that everything is warmed up and it was no problem then.
Barry & Sue Miller(extended RVer's, 6 mos + per/year)
04 Journey 39K, C-7, 330 hp, towing: 02 Dakota 4X or 2013 Ford Edge, Aero 5050XL