Recreational Vehicle Lpg Tank Valve/gauge problems of the 2004 Dodge Dakota

I bought my Dodge Dakota brand new from a dealer. I started to have problems with it almost immediately after purchase. I'll briefly list these failures. While driving in very cold weather (winter). I was driving with the heater on, a large volume of engine coolant came pouring out of the dashboard heater vents. This was repaired by the dealer. Within that same year the fuel gauge and check engine light would come on whenever the gas tank became half empty. At this point the fuel gauge would drop to zero fuel, corrects when gas cap is tightened or fuel is added. Plastic piece broke off in transmission at ~ 52,000 miles, I had it replaced and now have a crack in exhaust manifold which caused thermostat failure, water pump failure and leaking of all of the engine coolant. Unable to weld the manifold and mechanic had to install heat shield to prevent all of this from happening again. Now when I start the vehicle is sounds like it might explode! this horrendous noise softens after a few minutes. I don't run the heater anymore as I smell a very strong odor of exhaust fumes when heater fan is on. Vehicle occasionally shuts off when idling at ~500rpm.