Ok I have a 1999 Ford Ranger 2.5L 4x2 manual transmission.
The truck has not been driven to much in the past two years...but I would start it very two or three days.

Anyways I recently moved and the trip was 80 miles...30 miles into the trip my clutch all of a sudden started acting up. I start to approach a toll booth when it starts in...I begin to down shift and when releasing the clutch it would not catch into gear until I reved up the engine, then it would catch. It did this in all of the gears until I made it all the way there. OK so I turn off the engine for 10 minutes.....then I want to move the truck to a better spot and the clutch would not go down at all (stiff as a rock) So I let it sit over night and in the morning the clutch started to work normal again. Then a new issue came up.... I could not put the truck into first or reverse when the engine was on but when the engine was off it would work with no problem.
Before the trip I did change the Trans oil...Advanced Auto Parts ATF oil

The Master cylinder was changed about two years ago at a local shop in Orlando.

I thought it might be the slave cylinder. Anyways

I sprayed down the clutch with some ZEP 45 Penetrating spray with PTFE and now I can change the gears into first and reverse and all the other gears with the engine on or off with no problem. I even drive it around the block with no issues. Oh and the fluid level is just fine and No leaks that I can see anywhere.

Any Ideas? thanks