Help diagnosing cylinder misfire and damp spark plug...

[Dnutt]

So a month ago my coil went bad on #8. Replaced coil and checked both plugs which looked fine. A month goes by and I'm getting same misfire code on 8. Replaced coil again even though it's running ok. Checked plugs and 1 plug was fine but the other is damp. Not sure if it's oil or coolant. Why would 1 be damp but not the other? I can disconnect batt to clear code but comes back within 5 min of driving. Any ideas????
188k on 2019.

 

[kapinallinen2]

So a month ago my coil went bad on #8. Replaced coil and checked both plugs which looked fine. A month goes by and I'm getting same misfire code on 8. Replaced coil again even though it's running ok. Checked plugs and 1 plug was fine but the other is damp. Not sure if it's oil or coolant. Why would 1 be damp but not the other? I can disconnect batt to clear code but comes back within 5 min of driving. Any ideas????
188k on 2019.

Lick it, if it tastes sweet then it is coolant.
You could also use a boroscope to look into the cylinder.
If the top of the piston is clean, that would indicate a coolant leak. If sutty or black, then oil bypassing the rings.
No idea why one plug is wet and the other is not.

edit: I would do a compression check while at it.

 

[theblet]

Might be an injector problem, and not the spark. Try swapping the #8 injector with another one to see if the issue moves.