1999 Dodge Truck 1999 Dodge 1500 5.2 with 111000

The problem started the day befor I left on vacation. I was driving around the city getting everything ready for the trip and while at lights it would just die and would not start back up unless I held down the gas. I checked and cleaned the battery terminals becasue someone told me Dodges need perfect terminals, that had no effect on the problem. So I get back from vacation it had been sitting for 8 days, I start it up it starts to back fire and rev. I though maybe just a fule problem let me see if I can blow out a particle, I step on the gas no response still backfiring and running very irratic. It finely gets going and at about 20 to 25 mph it gets a sudden birst and runs like its brand new? I have to stop at the light and it dies and since then I have not been able to get here to run right. I put new rotor and cap on so far, just dont have a bunch of money laying around so I thought I would turn to the pros to give me some pointers. PS the fule pump works properly can here it running