Yes loose plugs can be a big problem if not fixed. I would replace those wires. Unless you want to pull the intake again I would bite the bullet and do it right. Also with all the oil on top of the plugs on that one bank, you need to do the valve cover gasket and the plug tube seals. Oil getting to the top of the plugs can cause a misfire as well.

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..