Spark Plug - Motorcraft SP-439-AX

["Platinum Spark Plug", "75,000 mi OE Mfr Recommended Service Interval", "Gap 0.044\"", "Plug Material: Platinum", "Interchangeable with SP-439-A"]

Spark plugs ignite the compressed air/fuel mixture in each cylinder, and their condition directly affects combustion efficiency, fuel economy, and emissions. Signs of worn plugs include: difficulty starting, a rough idle, a hesitation or misfire under acceleration, reduced fuel economy, or a check engine light with misfire codes. Replace spark plugs on schedule - new plugs restore clean ignition performance and can noticeably improve fuel economy.

Motorcraft is Ford Motor Company's OE parts brand, manufacturing components to exact factory specifications. Of particular relevance for Mazda owners: during Ford's partnership with Mazda (2000s-2010s), many Mazda vehicles including the Speed3, Speed6, and NC Miata shared Ford platforms and components. Motorcraft represents legitimate OE-quality parts for these Ford-era Mazdas.