1999 6cyl GMC p/up... won't start again!

[Psion5]

Ok, My 1999 GMC 6cyl vortec half ton pickup last week would not start (it's winter where I live)... I got it towed to the Automotive repair shop in my town... They diagnosed it as a bad distributor. Fair enough, they installed a new distributor cap and rotor (according to my bill) and got it running perfect.... 4 days later... I couldn't believe it... Again it won't start!!! I crawled under the hood and sure enough there was a new distributor there... So another fried distributor (I have to assume it's the same reason it won't start again) in less than a week? Before I go back and have them take another look... is there something they are missing? I have had no major issues with this truck until now. Before I let them install a yet another distributor or try and hit me up for more money by replacing something that isn't causing the starting problem,... is there something else causing my distributor to go south? By the way it cranks fine and the battery is strong...

Any advice and help would be appreciated.

Thanks
Richard