Misfire when engine is warm

98 Transport with 160k the engine runs fine when it starts but after it warms up it'll misfire. Codes tell its cyl #1 pulled the plug (ugh) and it looks fine. So I'm suspecting a coil pack. Wires are less than a year old.
Any ideas? Suggestions? Anyway to test a coil pack?

Tested the coil pack with an OHM meter 5K-7K ohms across the secondary side. Mine was 6K but I suspected that it would pass, the engine runs fine until warmed up. Swapped out the coil pack for cyl 1-5 $20 and that fixed it. :)