Backfiring is a sign of a lean condition, probably from a lack of fuel. Fuel filter is probably clogged. You can get fuel to pressurize the fuel rail but when in constant demand the volume drops and causes a lean condition.

I am not sure about a 2002 but my 94 Ram has an in-tank pump/ filter combo. I replaced both at the same time when the time came. I had been having backfiring issues, and the final straw came when I was trying to run 70 on the interstate, it wouldn't do it.

Edit- Rockauto shows an inline filter for your 02 rather than the combo unit- if you do have to replace the pump stay away from the spectra, I put one in a Cirrus that lasted 9 months.