do any of yall trucks when you first crank it up does it sound like a rod nockin or a lose rocker arm its only when it first starts then it stops it was my first time hearin it tonight i had my door open why i started it up an i herd it for about 5 or 6 sec or so then it stop??

 

Mine did the morning after I put synthetic oil in....hasn't done it since though.

Yours could be a little bit of piston slap...the metal heats up and expands making the piston fit the cylinder better which causes the noise to go away.

 

prolly just the lifters.....it makes that sound till oil can get to the lifters and then it goes away....i'm guessing thats what it prolly is

 

thats somewhat i was thinkin i was just runnin it by yall see if all is good