The filter may be lose if this is not the case the threads around the filter may be "stripped". Try changing the filter if this does not work I would take your vehichle to a certified mechanic.
an oil leak
The problem is a leak inside the high pressure oil system. When it is hot the leak expands and causes the truck to not start.
If the casing is spilt a filter will leak an incorrectly installed filter will also leak.
Change your fuel filter. If if it only does it when the engine is hot, check for a coolant leak.
could be a vacuum leak
A leaking gasket, a leaking filter, or a leaking drain plug....
get the seals checked out around the transfer case and tranny
Check for any electrical connecter behind the fuel filter housing. Check for bare wiring / shorts, exc. this may cause a short and been near the fuel filter housing it may cause fire. Be very careful and look for anything out of place/ or any thing advised.
Many possible causes: vacuum leak, clogged fuel filter or line, injector problem(s), faulty fuel pump.
A leak.
you need to be more specific... what kinda leak is it?? most likely engine oil or transmission oil, check on your dipstick and make sure the engine is at proper level, to check the transmission you have to crawl under the truck and remove a plug on the side of it. also how is the truck running rough??
Look for the tube that takes the condensed water out of the cabin these sometimes get knocked loose by the feet of the passenger's