Lately I've been hearing a knocking sound on start up that only lasts for about 30 seconds or so while the engine warms up. Does anybody else have this problem? If so what is it and how do I go about fixing it?

 

time for some new pistons sounds like

 

I'm guessing by the post count that you recently purchased the car? LS1s have a piston slap characterized by starting a little after it is first started cold and lasting about 30 seconds to one minute. It is caused by the short piston skirt, piston size etc. but will do no harm. If it knocks after it starts to warm up it's something different and we'll need further info.

 

piston slap, ftl

 

It's cold out side, it's a GM product, get used to it. It sounds like what you are hearing is someting that every LS based engine encounters on start up with a cold motor.

 

Hey thanks, yeah I did just get the car about a month ago and I already have big plans for it, anyways it has been really cold here in delaware as of late if that makes any difference. It doesn't do it all the time on start up but when it does, it's always cold and it only goes for about 30 seconds or less.