This is a way off topic but I don't know where else to even look. Its for a 2004 Silverado 2500HD...I bought a set of ported heads for it because I hade several exhaust manifold bolts snap off. Short story, I threw in many new parts on it since it was apart and now that its back together and runng it throws a P0300 code.

Injectors tested and passed, all spark plugs fire...hoses were inspected "by me" so not 100% sure there isn't a hairline crack on them. New intake gasket, new crank positioning sensor...I also did a catalytic converter inspection (pressure test), its all good. I have not touched the O2 sensors.

The truck idles great, it turns great and starts right up...no leaks :-) but as soon as I pass the revs over 1500rpm the service engine light blinks and gives the code. If I don't rev it the code does not come up. I left it on idle for 5 minutes...engine temp got up to normal operating range with no code but as soon as I gave it gas it started blinking. When I drive it it feels like it wasn't to bogg down...lack of power...

Any ideas?

 

The old P0300 can sometimes be a hard one to find. It means there is a random misfire. I don't know about the idiosyncrasies of the Silverado, but I think I'd start with plugs and plug wires. You could wait until it's dark, take a squirt bottle and mist the wires and plugs and see if you can see any arcing.

 

There are some details about modern engine that I still don't know just because I've never had to deal with it if you know what I mean...wires are Bosh and brand new but even after that I wanted to test if there was a spark the boot that goes to the actual spark plug has metal shield to protect it from heat. I was waring a gove when I was holding it to the block to see if there was a spark...let me tell you I saw the future...it felt like I got kicked in the chest by a damn horse. Took me 5-10 minutes to get off the floor. I found out that coil works great! LOL However I was under the impression that arcing from plug to me was impossible...I'll try the spray bottle tonight...