My 2003 ford f 350 with 49000 miles on all of a sudden is running like sh_ _. on 2003 Ford F-350 Super Duty

Stering wheel vibrating due to engine running lousy at idle. It goes when i step on it. When i let off lousy again. joe

Asked by for the 2003 Ford F-350 Super Duty
pull fuel filter and see if any water in fuel. if fuel fine than explore ignition system. have a diagnostic run.