Disconnect each spark plug wire from both the coil and the spark plug and use your multimeter to check the resistance on each wire
The 05 DGCV Service manual includes this table that specifies the maximum spark plug wire resistance per wire:
Since a crack in the wire's insulation or oil on the wires or boot can cause an arc and a misfire.
I recommend replacing all of the plugs and all of the spark plug wires as the first step in diagnosing the issue
I replaced my 05 DGCV's 3.3L's spark plug wires at 174.3K, my replacements were the ACDelco 9466I (Rock Auto, $27.79)... no issues to date at ~232K, (RockAuto no longer lists these plug wires for the 05 3.3L, but the ACDelco site does list them as compatible)
Or visually inspect and clean each wire
Remove all traces of oil near the plugs and replace the valve cover gaskets if there is oil at the base of the plugs
Route the plug wires by using the factory wire separators to maintain the spacing between wires and other metal surfaces
Regarding coil replacement:
Replacing the coil is a good move if you have replaced all the spark plugs and spark plug wires and still have a misfire issue
The factory coils are amazingly durable considering the location of the coil on top of the engine w/ all the engine heat that they are subject to
I replaced my 05 DGCV's 3.3L's coil at 174.3K, my replacement was the Standard STD-UF305 (Rock Auto, $39.79), no issues to date at ~232K