I have a 93 GMC 1/2 ton pick-up with a 6 cyl.
When it's humid or raining it chugs, coughs, and sputters. I've decided it may have a hairline crack in the dist. cap.
Would I be able to replace this myself? Any advise would be apprecitated.

 

Spray spark plug cables ,distrib. cap with WD40.This dissapates the moisture and no residue of WD40 remains after a period of time.Better than spritzing with water.Start of with cables first, then if problem persists then WD40 the cap.Make sure the air breath hole usually underneath the cap is unplugged or humidity will build up inside and cause the problem you mentioned.It happened to me once and my breather hole was packed with dirt.

 

Pitch the cap, rotor, wires, all the filters and spark plugs.

Treat it to a full tuneup. Well worth the time, effort and money.