snapping noise by the dist. cap

[88canadianvette]

i have this annoying snapping noise by the distributor cap.
its on the passenger side and ive replaced the cap and rotor so i dont think that is the problem. the spark plug wires look pretty old so i checked them for shorts and they came up allright.
the car is will miss and stumble when the snapping occurs. any ideas what this problem might be? [ im thinking maybe a coil? or spark plug wire?]

 

[Rowdy1]

Sounds Like

A plug wire, maybe the boot at the plug, you're loosing spark some where. Check it in total darkness, you'll see it right away.

 

[88canadianvette]

i thought of that. i went out last night and looked for a spark jump. but didnt see any. thats when i used a short detector light and ran it up and down the spark plug lines and i still couldnt find a short. [thanks for your reply]