GMC Repair: Cap and Rotor Problem, gmc sierra, distributor cap

Question
I have a '96 GMC Sierra with a 5.7 liter Vortec. Over the past year I have had to replace the Distributor cap and rotor 4 times.  It starts missing a little at a cruise and eventually cuts out all the way.  I replace the cap and rotor and it runs fine for a month or two.   The caps usually have a blueish film on the inside.  I replaced the coil the last time around but it didn't fix the problem.  I was told to check the bushings in the distributor housing but there does not seem to be excessive play on the shaft.  I have 146k miles on the truck and other than this it has been very dependable.  Any ideas?
Thanks in advance for your help.
Kev

Answer
If you would send me some pictures of the inside of the cap and the rotor as well as a picture of the distributor with the distributor cap "OFF" so I can see the insides, I may be able to help you.

e-mail your pictures to:

onlineautohelp@msn.com


akhnaton