Recreational Vehicle Lpg Tank Valve/gauge problems of the 2006 Chrysler 300C

My car has been cutting off every time I fill it up since I purchased it. I took it to the dealer on 12/01/2015 they said it was a faulty gas tank they replaced the tank on 12/14/2015. On 12/19/2015 I was going over 50 miles per hour and my car just cut off no warning. I was able to crank it back up and pull off the road and soon as I got off the road it cut off again this time a bolting light came up on the dash. I waited two minutes and crunk it back up it immediately cut back off and the bolting light again. I waited 10 minutes and it stayed crunk and I was able to make it home. The next day the same problem occurred again the rpm gauge just drops and the car shuts off.