1998 Dodge Caravan fuel problems

Like I said earler I did a complete tune up and replaced the fuel filter and the car ran better. The van gave a check engine lite on the dash. I erased the code and the van seem to run fine for a day or two then it just quit at night. My mother in law said she smelt fuel. When I got there the next day I noticed the fuel coupling that connects the fuel filter to the engine feed line came undone.

I first thought that I somehow just did not have the locking tabs engaged properly so I reattached and made sure. The van started fine but in about 20 minutes the van quit and I smelt fuel once again I noticed the coupling pushed off and check engine lite cameon again. I think it has to do with either the emmission systems fuel pressure reliefe system. I think the compenents that are involved are the purge solenoid, evap canister, roll over valves in tank and if I have one the leak detection pump but I could not find that om my car?