Dodge Repair: cap and rotars, dodge caravan, distributer

Question
Yes I am in the process of fileing suit against my mechanic because I feel I got the bad end of the stick. I have a 91 dodge caravan, first my mechanic claims that they use new parts, from 3/03/04-3/06 I have had three distributer caps and three distributer rotars put on my van. the mileage is 87,197-98,000 is this normal? i would like your expert opinion to use for my defense. My mechanic says it happens, I disagree. Please help.  

Answer
I feel it can be a number of facts that cause this problem like the following
bad coil or pack
faulty plug wires
a serious short
wrong type of spark plug
truck overheating
this is a all too common problem with this van so dont feel like your alone.