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16 reviews


Iridium Spark Plug Set [Mk3 Focus ST]

EcoBoost engines running substantially higher boost pressure or increased levels of tuning compared to the OE power output 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. Using spark plugs that are optimised for increased power ensures maximum performance.

Extensive in-market validation at extreme boost / cylinder pressures was undertaken to ensure optimal performance was achieved, whilst also making sure  reliability and drivability wasn't compromised in colder ambients.

Each set is supplied pre-gapped by mountune to optimise the setting and allow for easier end-user installation. 

The NGK LTR71X-II is one step colder than the original spark plug.

Focus ST 2013-2017
  • Smoother acceleration
  • Perfect for high boost applications
  • Supplied pre-gapped by mountune

Please note:Supplied in a pack of 4 plugs.

Customer Reviews
5.0 Based on 16 Reviews
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Filter Reviews:
    bhavin g.
    United Kingdom United Kingdom
    Great Product & Would Recommend For Focus ST MK3 Owners

    My engine was misfiring under load in high gears. Ordered these spark plugs, super quick delivery and install was very easy. Engine is running smoothly now under acceleration. Would recommend to all Focus ST owners.

    Christopher J.
    United Kingdom United Kingdom
    Spark plugs

    Great service fast delivery

    Adam J.

    A must have upgrade for the oem part. Car feels smooth and acceleration is a joy. Highly rated part again from mountune.