i have a 4.3 omc cobra just replaced the fuel pump and filters,cap rotor wires and plugs with ac delco mr43t. i have had problems with top end bogging down,then i throttle down to low rpms and it runs fine. i return to full throttle and the same thing happens. i have blown two spark plugs out of the metal seating (porcelean only). Bad plugs or something else?
