What causes coils to fail early?

Running with worn spark plugs, heat soak from exhaust, and oil leaks onto coil boots.

Can oil on a coil cause misfires?

Yes — oil from a leaking valve cover gasket can deteriorate the coil boot insulation.

High Severity

Ignition System

Coil on cylinder 4 fault.

Common Fix

Replace ignition coil

Estimated Cost (DIY)

$20 - $80

Failed coillikely

Wiringpossible

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What causes coils to fail early?: Running with worn spark plugs, heat soak from exhaust, and oil leaks onto coil boots.
Can oil on a coil cause misfires?: Yes — oil from a leaking valve cover gasket can deteriorate the coil boot insulation.

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