When you let it set, how much fuel was in the tank? Could be water consensation causing the problem.

Another thought, I had a truck that sat for about 6 months. I got it started, but when I tried to drive it, same problem. Stuttered and sputtered. Took the fuel filter out and it was clogged with varnish. Replaced the filter and all was fine.

03 TJ 5 Speed I-6 30X9.50 BFG KO's