This is a question for all you engine tuners. I have a 1995 F350 with 460 & E40D. Everything is completely stock. It runs OK right after I start it up, and for a few minutes. At some point it begins to miss when I try to accelerate. If I accelerate very slowly it is OK, but if I open the throttle just a little too much (which is really nothing "radical") it feels like someone momentarily switched the fuel off & on. Very similar behavior as when your fuel tank runs dry and you switch to another tank. Once it does this a couple times the "Check Engine Light" comes on and the engine stuttering will not stop. I can stop, switch the engine off and back on, and the Check Engine Light turns off and the stuttering is better, and sometimes cleared up until I open the throttle too much again. The problem is at its worst at low RPM, and eases up as RPM increases. So in summary it seems like it is triggered by too much throttle at low RPM. At high RPM it sometimes is still missing, however.

Here is what has been done so far:
1. A few thousand miles ago (and for a different reason) plugs, plug wires, distributor cap, rotor, fuel filter, air filter and catalytic converter were all replaced.
2. Last month a local shop replaced PCV valve, fixed a right-side manifold-to-exhaust pipe leak, and replaced all eight plugs again because the right bank plugs were all carbon-fouled.
3. I have this past week driven it about 1,000 miles and ran several tanks of gas through it, all with Sea Foam injector cleaner in them.
4. I stopped by an auto parts store to have the store employee read the engine diagnostic code. He said it was code 512, but his information did not identify what 512 meant. I looked it up via Internet and had to guess because I really don't know which of several mentioned diagnostic systems this truck has. OBD2? Anyway, I did find a 512 that said something about a computer power interruption.

My thoughts: It really feels like a fuel and air problem, rather than an ignition problem. So, could it be that the fuel filter is dirty again, or the fuel system is dirty and plugged?

Being it is fouling plugs, my first instinct is to look for a vacuum leak. It also plays right into the other symptoms you describe.

95 is kind of an off year, where it could have been the old EEC-IV otherwise known as OBD-I, which is kind of a misnomer. 96 is the first official year of what is often called ODB II.

Thanks. When the fuel filter and catalytic converter were replaced they did check vacuum and did correct a leak. But, it is good idea to make that check again. I will do that.