On sunday my K5 was running with a dead miss. Earlier in the day it drove ok but seemed to be a little down on power. The fuel mileage had dropped off in the passed week. That night it began running with a bad miss. The next day I replaced all the plugs and wires. Now it runs fine again. The thing that I'm concerned about is the fact that it has been only about 9000 miles since I last did plugs. What could have caused this? I have all the plugs on a piece of cardboard, labeled by cylinder number. I can post pics if it will help.