I have had 3 coils go bad in the past year. I just put this coil on a couple weeks ago. It ran great until the sputtering and backfiring.

Is there an other issue the truck could have that would be eating up my coils?

 

I'd really be surprised that 3 coils would go bad in a year. Condensers are famously poor quality nowadays. If you disconnect the condenser you can run a short time for troubleshooting, it just is bad for the point contacts.

If you are 6v (+) ground, make sure the coil is designed for that and is hooked up that way. Hooking up a coil designed for (-) ground on a (+) ground car will be bad for it.

Some 6v cars used a ballast but others didn't. The truck wiring diagrams don't seem to show one?

 

According to the "bench tests" all three read way out of specs ohm readings when truck would not start. I replaced with new coil(used same condensor) each time and truck would start right away and run fine until I would go out and it wouldn't start. This is the first time it started running bad while driving it in the 11 yrs I've been driving it. This time I replaced all ignition parts and it ran great... for a while.

Check me here... but I have coil connected with hot to ignition and ground to distributor...?

 

I had the SAME situation last fall. Could not figure it out until I pulled the coil. I was sure that the FlameThrower coil was still good, till I saw that the top had erupted. Replaced it with an epoxy filled solid coil, no problems since.
BTW, coil failure, especially new coils, is not unusual.