Bosch Ignition Coil N54 135i/335i/535i

Pencil coil insulation can heat-harden and crack, allowing secondary spark to short to ground. Symptoms include engine misfire--especially when cold or under load--a flashing check engine light, and diagnostic trouble codes.

OEM coils fit and work right, restore engine performance, and prevent costly catalytic convert damage that can result from persistent engine misfire.