Engine's Knocking....

[1slowdsm]

Would the timing just move by itself? I havent done anything with timing. I've looked at the belt like twice and thats it. At the Rock last time it was only in 3rd. It knocks every now and then when I'm just cruising around. I'll see if I can find someway to check my timing. I dont have a timing gun thing, but my cousin might.
*Edit* On a MMCD program does TIMA mean Timing Advance? If it does, how much is it supposed to normally advance by? Mine goes up to like 60 Degrees with no knock and then like 20 Degrees with knock.