Changed my oil today. Nothing scary in the oil, no metal, no water, none of that. It is still knocking though. So I'm thinking of putting some bg oil additive in it. Thoughts?

 

So it's been about a week since my oil change and I still have the knock. I haven't put any additive in yet because I have never liked putting additives in my vehicles. I also had my ses light come on the other day. Fuel it too lean. Is this a common problem with the Blazers? If so what's the usual cause? Fuel pump? Fuel filter? Vacuum leak?