Bosch two and four prong plugs make many engines run like shit... oddly, Hondas run OK with them but not as well as they can.

When I bought my Stealth, it had Bosch four prongs in the front bank and two prongs in the rear bank. It misfired like no other. When replaced with NGK coppers gapped to factory specs, it ran like a champ. Stay far away from any multipronged plug (Rotary no-prong, four section plugs aside... I live to educate :chuckles: )