Big Problem. Loud knocking noise at low rpm's and pinging noise

[pshaxe]

need some help pretty fast
ive read up on a bunch of stuff looking for answers and all i can find is it would be a rod bearing, for the loud knocking noise at low rpm's.
but could the piniging noise be the MAF sensor?
when i drive it, it almost sounds like a diesel but when i start to come to a stop thats when the knocking noise begins.
i took it to autozone and had them scan it, all i got back was that i had a cylinder 6 misfire.
so far ive changed the oil, which was pretty burnt, i just changed it 1000 miles ago to.
need some help, would greatly apreciate it.

 

[williams.cory]

how many miles are on it? whens the last time the spark plugs and plug wires were changed? You could clean the MAF. Could also be Camshaft Position Sensor

 

[pshaxe]

not in a while
its got 173000 miles on it
im gonna try an clean the MAF when i get home
i didnt think about the camshaft position sensor though
we had to change one out on my dads f150 a while back

thanks for the help