Q: PO300 Code. Cause of misfire

Exhaust leaks are not typically a cause of misfiring. However, intake manifold leaks can cause misfiring. Random misfiring (P0300) has lots of potential causes so you just have to perform a methodical diagnostic. Among the possible causes are faulty spark plugs, low compression, damage or excessive wear of spark plug wires and/or coils, faulty fuel injector, clogged EGR valves or tubes, burned valves, improper ignition timing, vacuum leaks, leaking head gasket, faulty camshaft sensor, faulty crankshaft sensor, faulty mass air flow sensor, faulty oxygen sensor, faulty throttle position sensor, faulty catalytic converter, and others. If you want the cause of the misfiring pinpointed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a misfiring diagnostic and the responding certified mechanic will get this diagnosed and resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.