Dodge Repair: fuel system, electronic fuel pump, vacuum leak

Question
I have 1998 Dodge Truck 2500 Quad Cab 5.9liter V8.
Recenlty I started having problems with fuel system I believe. The truck runs rough and sputerrs when idling or low throttle. It dissipates at high or full throttle. It has this problem about 50% of the time.I've added dry gas and drove about 5 miles. This seemed to help but then the problem reoccurred.It may be a coincidence but it started when all this wet weather in North East arrived.
P.S The new electronic fuel pump was installed 8 months ago.
Thank you very much in advance.

Answer
Steven,

Your fuel system may be the trouble, but may have an
egr problem, or a vacuum leak, or maybe your ignition
system is being affected by the wet weather.
Im sorry, but I cannot help much with this problem because I can think of alot of things it could be.