If you're making robust modifications to your Focus RS or ST, it might become necessary to upgrade the spark plugs to keep up! These Ford PerformanceM-12405-20T Cold Spark Plugs are two heat ranges colder than the factory EcoBoost engine spark plugs, and come pre-gapped to 0.028-in. (0.71mm).
Using spark plugs with too hot of a heat range can cause detonation, and conversely, using sparkplugs with too cold of a heat range can cause them to foul. In the long run, this has the potential to cause catastrophic engine failure, so it's definitely something you want to take note of!
Fitment: 2016, 2017 and 2018 Focus RS and 2013, 2014, 2015, 2016, 2017 and 2018 Focus ST
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