Hard to Diagnose P0300 Fixed

[Supermoney]

A few months ago my CEL came on for a P0300(random cylinder misfire). Truck ran ok but it'd shake on startup so I thought it was probably fuel related or maybe a coil packs causing a misfire on both sides of the engine. I replaced the wires since they were original but not the plugs since I did them about 3k miles ago. I also replaced my PCV valve and it ran a little better but still CEL. I noticed I was ever so slowly losing coolant and my radiator hose was not holding pressure so I realized it was my head gasket. It was a very minor leak so I got some K Seal head gasket fix and poured it in the radiator and within a day my CEL was gone, truck ran great and radiator held pressure. This could have easily costed me hundreds if I threw parts at it.

Slightly old bump, but its most likely not your head gasket. Your heads have a crack in them. Usually near cylinder 3. Very common issue. Is it still holding up though?

 

[Majkmichael]

Slightly old bump, but its most likely not your head gasket. Your heads have a crack in them. Usually near cylinder 3. Very common issue. Is it still holding up though?

Good point, never heard of that problem. They're still holding up good though.