Q: Would a leaking valve cover gasket cause a misfire?

A leaking valve cover gasket can cause a misfire if oil is leaking into the spark plug wells. But that is usually not the problem. Most often the misfire will have a separate cause. But a leaking valve cover can cause smoke, bad smells and even fire, so it is in your best interest to take care of it right away. If it solves the misfire problem, that much the better. In either case, you can contact YourMechanic to have a technician come out to your home or office to replace your leaking valve cover gasket and check out your misfire right there on the spot.