I've never replaced all coilpacks. Logically i understand the situation.
We can assume all coil packs have roughly same lifespan and should all go out roughly the same amount time. But I've always replaced single coilpacks unless its a rear bank and then I might suggest doing all 3 rears.
However I'm working on a honda fit. No exactly cylinder code, just a P0300 random misfire. It slightly misfires at idle but definitely at 3-5k RPM. Looking at the misfire counts, its primary on 4 and 2 but 1 and 3 still misfire as well. Reading the forums, seem like the motor likes to eat coilpacks at 75k. The car I'm working on is at 100k.
I replaced #4 and while it was the main cause, the other cylinders still misfire slightly. I'm tempted to sell the other 3 coilpacks just to rule out that.
We can assume all coil packs have roughly same lifespan and should all go out roughly the same amount time. But I've always replaced single coilpacks unless its a rear bank and then I might suggest doing all 3 rears.
However I'm working on a honda fit. No exactly cylinder code, just a P0300 random misfire. It slightly misfires at idle but definitely at 3-5k RPM. Looking at the misfire counts, its primary on 4 and 2 but 1 and 3 still misfire as well. Reading the forums, seem like the motor likes to eat coilpacks at 75k. The car I'm working on is at 100k.
I replaced #4 and while it was the main cause, the other cylinders still misfire slightly. I'm tempted to sell the other 3 coilpacks just to rule out that.