Motorcraft Spark Plug Set of 4 - SP-537
Focus ST 2013-2018
Focus RS 2016-2018
The EcoBoost engine operates under extreme conditions
including high cylinder pressures. The spark plugs are subject to rapid wear
rates, even at standard performance levels. Engines running higher boost points
or increased levels of tuning can experience reduced spark plug life resulting in
lower engine performance, misfires and rough idle. Increased wear is typically seen in the form
of increased spark plug gap and degradation of the electrode.
For optimum power and performance we use genuine Ford
Iridium spark plugs and replace them every 10,000 – 12,000 miles.
For standard engines and mountune performance upgrades,
we recommend and use standard heat range spark plugs. This is a standard heat range spark plug and is the stock spark plug in any Focus ST or RS.
- Genuine Ford Motorcraft