My 2008 Chevy Equinox is showing the code P0008. It is now fairly sluggish with loss of power, but it seems to come and go. I'll get in it one time and this will happen, I'll get in it again and it seems to run fine. When I start it (sometimes) I can hear a very slight knocking, I'll shut it off, restart it and the knocking will go away. I did a little research and it says it's caused by the camshaft and the crankshaft being misaligned, it recommends that the primary drive and both secondary drive timing chains be replaced. Is this the only cause for the P0008 code and if so how much would it cost for repairs?