My name is Trent Hansen. I have a ford 2002 triton V8 E350 with 304,000 miles. It has a stuttering problem when accelerating. Even more so when going uphill. However, the stuttering problem only occurs when I try to accelerate quickly. I can tell that some of the Pistons are not firing up. I replace the spark plugs a couple years ago, so I tried replacing the fuel filter, and that helped a little. Maybe it is the fuel pump?