Plug wires arcing
 

'87 N/A: I put a set of Magnecore 8.5's on it that I took off of my old '91 N/A. Near as I can remember, the wires have maybe 25000 miles on them. Shortly afterwards I was driving and it started bucking. I realized that the problem was probably arcing, because I hadn't done anything else to it. Raised the hood, made sure all of the wires were well seated in the coils and to the plugs. Moved the wires around such that none of them touched another one. Problem solved.

Sorry about the long intro...my questions are, what makes plug wires arc? And is this a common problem, or are the plug wires bad?

What do your plugs look like...

Remember. Electricity takes the path of least resistance. If the plugs are completely shot and the wires have bad insulation (Defect or rubber cracked and old) or the air is moist, spark doesn't go to the plug, but out somewhere else.

Check the plugs. Be sure all connections are solid again. And lastly, once everything's back together, fill a spray bottle with water (Or you can use windex or something) spray your wires lightly. If they arc, it's time to get new ones.

25K miles seems fairly short for wires though.