If your not familar with the firing order replace one plug at a time and put wire back on the plug ...after you have replaced all the plugs then replace the plug wires one at a time comparing the length of each wire to the replace wire ....this way you won`t get them mixed up ...
Don`t do like a buddy of mine did and pull all the plugs and wires and not knowing where they went back in firing oder ...
he just didn`t know it mattered
