My car (with 175k miles) has started to sputter occasionally while driving. It happens briefly and lightly. It's almost as if the car is about to run out of gas and the engine is going to shut off. The check engine light is not on.
I decided to replace the spark plugs. (I'm the second owner and unsure if they were ever changed.)
While replacing the spark plugs, I noticed one of the ignition coils has two discolored bands around it. Is this okay to use or should it be replaced?