how to change the plugs on 94 trooper?

I have pulled one wire out and have tried to unscrew the plug. but it looks like there is a rubber boot around the old plug that is stopping me from getting my socket on the plug.

Help

Are you sure that you removed the plug wire properly? That year of Trooper has a rather strange plug wire. The wire has a connector on the "coil" then runs to the engine passing through a rubber cap connected to a long insulation tube. I have had an older wire break off at that top boot.