The Norcold N611 fridge in my 2012 North Trail Hybrid runs fine on electricity but runs intermittently on gas. It is hard to start-may work after 2 or 3 tries. It goes "gulp" "gulp" "gulp' when it doesn't start. May not start at all but but then will start, sometimes on the first try, several hours later. When it does run it cools fine. But it cuts off in a few hours. The longest it has ever run is 6 hours until today when it sat out in front of my house and started the first try and ran like a pro until I cut it off. The dealer is blaming it on the altitude and he doesn't have a solution. I bought it in Colorado Springs which is at 6500 feet. All the best camping is above 8500 and generally is without hookups. I never had any such problems with my 2003 Cub even at 10,000 feet. I, also, have some heartburn with being sold a trailer with a fridge that now the dealer says won't run on gas above 5500 feet. He sold it to me 6500 feet for crying out load. He pointed out that was what the Norcold owners manual says. And who reads the owners manual for a fridge before they buy an RV????? Any and all ideas will be appreciated.