Alot of sputtering and back firing

smoove mood

Oh Baby I Like It Raw
My 87 has been sitting for abt 6mo's I changed the starter and ignition module. Added premium 91 octane and some fuel booster. I finally got it to crank but the idle is very rough and there is a motor sputtering and back firing happening. Ive let it run for abt 40 min but i dont want to damage it. What should I do? :confused: