Chevy 2006 Express 3500 utility box truckcode p0300 what's the most common problem cause

Question

what's the most common cause for this error code

Answer 1

P0300 Random misifre

The most probable cause. would be a mechanical condition. this is where the intake valve and the exhuast valve tends to develop a crack between the valves, Doing a compression test misses the mark, it when it is doing a running compression test do you find the problem.

 When a P0300 show check the sparkplugs condition. Here is a P0300 with a fouled sparkplug for the number 5 cylinder,

Doing a running compression test helps pinpoints the problem rather than doing a compression. Here is running compression being done on a suspected cylinder, a good running compression whould show above 65psi, what here is 40psi.

 The fix was to have the crack fixed, this occurs between the intake valve and the exhaust valve.