Started (pardon the pun) having misfires on start up on 'ol Blue a few weeks back ('96 Ram 1500/5.2, never rebuilt~250K). Being the lazy bozo with a back up vehicle ready to go, I instantly got right on the procrastination train and figured that since the 'misfire' only lasted a minute or so, whaddo I care?!? Valve stem seal, cracked or leaky cylinder head...who knows, who cares?
Anyhow, one day whilst a few miles from home, the battery craps out in a spectacular manor. I replaced it and voila, no more misfire on start up.
Related, can't say fer shore, however, it's been about 3 weeks now n no more misfires! Hope this helps someone else with similar problems and an old battery.

 

Yes, a bad battery can cause all sorts of issues, misfires being one of them.

Glad you got it sorted out and have the truck happily back on the road.

Thanks for sharing.