Well I just took of the valve cover off to check and see if there was a bent push rod and cranked it up and everything was moving freely with no unusual sound. I checked the codes again and it wasn't a P0605 code it is a P0645 code! So I have a P0645 and a P0305 code which confuses me even more cause the 0645 code is an A/C clutch code. What would an A/C clutch code fit in with a misfire code and the knocking???? Any ideas on this???? I also checked the plug wires and they are on tight. Thanks for all the help so far guys even though I haven't figured it out yet i appreciate the help so far.

 

By no unusual sound you mean from the upper end but you still here the knock?

Not to harp on you but have you pulled the plug? I'd start there if I have a misfire.

It could just be coincidence that the a/c clutch is throwing a code.

 

Its a bottom end knock, predominately after idling for a bit. I changed the plugs, wires, and cap. I also checked to see if I was getting spark to the #5 cylinder and I am. I unplugged the battery and reset the codes and the check engine light has not come back on but still hearing a knock along with the truck shaking a bit.

 

How's the oil pressure?

 

Oil pressure is normal. I'm starting to wonder if I have spun a bearing.

 

Well I found a blown head gasket!!!