How do I test an ignition coil?

Swap it with another cylinder. If the misfire moves, the coil is bad.

Can a bad spark plug kill a coil?

Yes — a worn plug with too wide a gap forces the coil to work harder, shortening its life.

High Severity

Ignition System

Coil on cylinder 1 has a circuit fault.

Common Fix

Replace ignition coil

Estimated Cost (DIY)

$20 - $80

Failed ignition coillikely

Wiring issuepossible

ECM driverunlikely

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How do I test an ignition coil?: Swap it with another cylinder. If the misfire moves, the coil is bad.
Can a bad spark plug kill a coil?: Yes — a worn plug with too wide a gap forces the coil to work harder, shortening its life.

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