Quick compression question
 

when doing the check do you need to take all the plugs out or just the one you have the gage in?

Just the one you have the gauge in. if you remove the upper plug to install the gauge, then remove the lower plug, it won't build any compression because the air will go out the lower hole.

Remove the front and rear TRAILING plugs. If you just remove 1 of 4 plugs, the compression the adjacent rotor is creating will slow down the engine speed and could cause erroneous results.