Truck was running great now it wont start. 1996 Dodge Ram 1500 5.9

I just got this truck and it run fine but if it would sit awile and you go to start it would take about three cranks to fire up but if you turn it off then try it it would start right up with no problems. So the hard start did not bother me. So now here is the problem I went out this mourning to start the truck and it took about three cranks but when it started it would not idle if I let off the gas it would die but it would start right up so I drove it around the block almost did not make it home when I pulled in the drive way it died and now it wont start at all it will try but wont and it makes a laud backfire out of the tailpipes. I checked and I can here the fual pump hum when I turn the key on and I do and I also checked my coil and am getting lots of fire I pulled one of my plugs and it is black and wet with gas. Can you help me.