trailing plug never fired
 

I have 20k on my rebuild i decided to pull the plugs the other day and check them. The trailing plug on rotor 1 still had the flat tip on the electrode the other three plugs where rounded. So i checked the plug to see if it was fireing grounded it out and cranked the motor nothing, bad plug since new im thinking. I got new plugs ngk platnium and the car runs smooth as hell and no break up in the higher rpms either but whats really strange the air fuel ratio is richer now than it was.