Question

I have a 2009 Hummer H3T 5.3L with engine code P0300, what is the meaning?

Answer 1

Hi there,

P0300 is either a random cylinder misfire or multiple cylinder misfire. This can be the result of several different things. Sometimes an intake manifold gasket leak will cause this, low fuel pressure, it could even just be time for a set of new spark plugs.

Answer 2

P0300 HUMMER - Cylinder Misfire Detected Random Cylinders

Read more: https://www.autocodes.com/p0300_hummer.html