well i,ve got a problem, seems i,ve got this miss in the mid range of throttle but if i stompo it,it goes away but then returns as the rpm,s slow. i was planning on replacing my fuel filter today any way and after i finished i put in a can of barsdahl and filled it with premium. took it up on 190 and did the loop of Dallas with the sounds playing. it still did it through the trip. the plugs only have 30000 on them but the wires are original. i,m thinking of changing both,if not to say i did that.my question is this:with no code showing,could this be it or should i look at something else like the egr valve(original) or O2 sensors(they,ve got 40000). specs:97 S/C 4.6l W. 75,000 miles

 

I had the same problem during the first week I owned my truck.
In my case it turned out to be a bad coil pack, fixed under warranty.

 

This does sound to me like a bad coil as well. Check and see if there is coolant or even simple moisture collecting on one. I think there has been an issue of coolant leaking out of the heater core onto the #4 coil on a lot of the 4.6L's. A bad coil can have an issue at only certain RPM/Load ranges. It is fine at idle and WOT but not at a steady speed.