Spark Plugs Gen-2 1.6 (PW811750)

Proton’s number for the S4PH plug is PW811750, and the plug in the box is an NGK BPR6EF-11. Buy four; the engine is a four cylinder.

The “-11” in the NGK code is the pre-set 1.1 mm gap. Do not trust the gap out of the box if the car has been sitting or the plugs have been handled. The gap figure itself comes from the NGK code, not from a Proton document checked here.

Copper-core plugs of this type are cheap enough that there is no reason to stretch the interval. Replace them at the service interval and keep the old set in the box as spares if they are still firing cleanly.

If the car misfires after a plug change, check that the plug caps are seated fully before buying coils or leads. A loose cap feels exactly like a failed component.

Verified against Malaysian parts listings naming PW811750 and NGK BPR6EF-11 for the Gen-2 1.6 S4PH, checked 2026-10-26. Retailer listing, not a Proton EPC.