I have noticed coolant loss and my 5.4 is running rough / missing, I have noticed that with the cap off the coolant reservoir the water level will drop 2 or 3 inches when I throttle it up. Then when I release the throttle the water bubbles back up to a normal level, also I have what appears to be water dripping out of the tailpipes. Could this be a head gasket or can this be something else

 

Hello Greg i have know nothing about this. Bump for you post..!!

 

Moisture coming out of the tail pipe could indicate a problem, but it could also be condensation. Depends on the outside temp, humidity etc.
You didn't say whether you are having to add coolant.
Steps you might consider and they are, pressure test the cooling system and see if the pressure drops.
A compression check.
Check for any misfire codes, it could provide some direction to a particular cylinder and if that is not available you might remove the spark plugs to see if you can see any particular difference in the appearance of any one plug compared to the rest.