Losing Water

I have a V6 94 ranger that is losing water, I see nothing in the oil and no bubbling in the radiator and nothing leaking on the ground where can the water be going?

Watch for smoke in the exhaust. Use a free loaner pressure tester it looks like the picture in the link. Advance,Auto Zone,Pep Boys,O'Riley's have them.
http://www.autopart.com/tools/toolsmain/tool/T_7050.htm
Just look under pressure sometimes a water pump will leak seal up and start leaking a week later.

We ran a pressure check today and lost very little. Pulled the plugs and found no sign of anti freeze on them. Starting to wonder if this may be a issue that only shows up after the truck gets warmed up say at high speeds. Maybe a crack in the head or a small crack in the gasket that opens up the warmer the engine gets. What ya think?

If you have a pressure tester pressurize the system and run the engine if the gage pulses you have a blown head gasket.
A radiator shop can run a gas analysis if you have combustion gas in the anti freeze its a sure sign.

I have the same problem. Turns out I have a head gasket leaking on the left bank, but its an external leak, just behind the exhaust manifold, and was hard to detect. It only leaked when warm and was slight enough that coolant dried quickly on the outside of the hot block. I used a block sealer, it slowed it down but still weeps. I'll wait til it gets worse to make repairs. Smell your exhaust, if it has a bit of a sweet smell, one or both of your head gaskets is leaking internally.

My 1994 4.0 ranger has used a little antifreeze for about the last 40k. I have yet to locate where it goes to but it losses about a Pint and antifreeze every couple months. I'm still waiting for it to get worse to fix it

In my '95 Ranger, it was the heater control valve. It had broke in two spots but I guess the pressure of the coolant rarely got high enough to push it apart. Or maybe because the heater was rarely used.