Additionally, remove adjacent plugs together as a head gasket leak between cylinders can be masked if you don't.
If you have a low reading, a couple of squirts in to the cylinder can help isolate the problem. If the pressure comes up retesting after adding oil, it points to worn rings/cylinder wall. No change points towards a bad valve.
Four wheel drive allows you to get stuck
in places even more inaccessible.
62 88 reg
67 NADA x2
74 Lightweight - The Antichrist (tag 6A666)
95 D1 - R380
95 D90 - R380
97 D1 - ZF