[WorkTruck]

I just got a '92 2500 6.5L. When it hasn't been ran for a while, it starts fine and runs good. After it warms up for a while, it starts to run rough. Eventually it will die at a stop light, and it won't start without putting the gas pedal all the way to the floor for a while. Once it starts, it still runs rough for a while then smooths out. Let it cool down for a couple hours, and it will start fine, then dies. Same starting routine as before, then it will stay running. It only has 59,000 miles on it. Just put a fuel filter on it yesterday. Any ideas? I hope it's not the injector pump. Should I try some fuel system cleaner? Any help would be appreciated.