!!Off Idle miss/ Midrange miss!!

I own 1999 S10 Blazer, 167,000. I have an off idle miss that I attribute to moisture getting in my cap. Although I have tried to seal it up as best I can with ignition sealer, it will still miss. After I have it up to speed I can feel it slightly miss about 55mph. It has new wire set and cap/rotor. I haven't checked the spark control module under the distributor yet to see if the grease has dried up and allowing moisture under it. But does anyone have anything else to suggest to check?