P0305 Mazda -

Question

2004 Mazda 6, V6.

Check engine light P0305

ONLY misfires when engine warmed up. Runs fine cold.

What's most likely cause?

Answer 1

P0305 Misfire number 5 cylinder

When a misfire occurs there that means that cylinder is not contributing sufficiently. this can be mechanical. a crack between the intake valve and the exhaust valve. or a cylinder head leakage which result in coolant loss, ignition coil can be at fault so could the fuel injector. If this only occurs when the engine is warm its more than likley a result of a mechanical condition.Doing a leakdown test is more accurate than a compression test.