P0300 on a Chevy: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

If the check engine light is flashing, stop driving — a severe misfire can damage the catalytic converter. A steady light is usually safe for a short drive to a shop.

What P0300 means on a Chevy

On a Chevy, P0300 means the engine computer sees misfires jumping between cylinders instead of on one fixed cylinder. A misfire means a cylinder is not burning its fuel properly, which wastes gas and can damage the catalytic converter if left alone.

Is P0300 common on Chevys?

P0300 is a common sight on Chevy V8s like the 5.3L in the Silverado and Tahoe, plus the 3.6L V6 in the Equinox and Traverse. Worn spark plugs and ignition coils lead the list. Intake manifold gasket leaks and injector issues also cause random misfires as these engines age.

Commonly reported on: Silverado, Tahoe, Equinox, Malibu.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking engine
Loss of power or hesitation
Poor fuel economy

Common causes

most common: Worn or fouled spark plugs
common: Failing ignition coils
common: Leaking intake manifold gaskets
less common: Clogged fuel injectors or low fuel pressure
less common: Low compression from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace worn spark plugs	Yes	$60–250
Replace failing ignition coils	Yes	$100–350
Replace leaking intake manifold gaskets	Mechanic	$300–700
Run a compression test to rule out internal engine wear	Mechanic	$100–200