I have a 08 mercury 150 efi thay i run every weekend fishing out of my 08 186 triton and last month i replace a coilpack for cylinder #6 that was bad and it was back to runonh great going 55-59 mph turning almost 5900 rpms and this weekend had a tournament, motor was running fine throught out the whole day then later on in the day i noticed i was only going 49 on full throttle and turning only 5100 rpms ( which is the same thing it was doing when my coilpack went out only a month ago ) checked the motor out and cyclinder #4 wasnt firing, spark plug is fine, now im pretty sure its a coilpack and im starting to wonder what is making my coil packs go out? Anyone got any ideas?