I finally got the blazer running really good and smooth, Drove it 4 times, on the 5th start up, Didnt want to run for nothing. Wanted to die under idle, black smoke everywhere, and sputtered and backfired teh whole way home. Got it narrowed down to it missing on a cylinder or 2, not sure which. Pulled the plugs on the Pass. side of the block to find them ALL nasty black and nasty. Pulled the distributor cap, and found this- Notice the ribs missing and a line cut into the wall between posts, then the big notch in the nipple for the coil. The cap and rotor were both set on the distributor flat and tight. I pulled out my old cap, and it looks the same as this new one, which is only a few months old. What is going on? Any help guys?