I learned valuable lessons after months of back and forth with a similar issue...
Replaced
1 battery
1 starter
1 coil
1 plugs
1 +/- leads
Buy parts local and avoid mail order hassle if parts don't fit
Buy quality napa parts worth the few pennies extra
Replace the cheap stuff first
And most importantly:
Check the grounds
When I ran out of options and replaced my +\- leads on the battery I found out that the ground was loose. Incidentally it was attached to my exhaust manifold so when it got hot the grease melted and made its way under the lead. I have since experienced the issue again but at that point I added a body ground into the mix. My issue got so bad the truck would only start when there was high humidity.
