Fuel pump problems

I have a 93 Dakota, 3.9 engine that recently the fuel pump went out of. Replaced fuel pump and filter and all seemed well. Within a short time it left me stranded. It seemed after I let it sit awhile I could get it started and get it home. It seemed like it would do it after it was driven aways or warmed up.(It's hotter than crap here, as in alot of the US). The other day I only drove it 3 miles and it wouldn't start. I've checked out the relay and made sure the gas cap was venting properly. Any ideas out there. I've only got about 100 miles on this pump and hate to replace it if this isn't the cause. I don't have a fuel pressure gauge, but do know where I can borrow one. Anyone out there have any experiences like this? All comments welcome and thanks in advance.