I have a '99 Escort that starts, idles and cruises fine, but sputters or jerks when accelerating normally, however it is very inconsistent. It can sputter once or twice or so bad that I have trouble getting up to speed. If I floor it, it usually doesn't sputter and accelerates normally. I had a CEL for a #4 misfire that eventually went away, but eventually came back. What could it be? I've already replaced the fuel filter. Wires and plugs are 1-2 years old. In the dark I can see an arc from the #4 boot to the block. thanks, Mark Fike