I need a air filter but don"t have the big bucks for a K & N round type filter. I have a amsoil square filter in the truck now. It came with the truck and at this point is very dirty. I could clean it and put the amsoil oil back on it but don't have a clue on how much you put on the filter. I don't know how old the filter is. I believe the guy who owened the truck before me added to much oil after cleaning because it's oily in the bottm of the filter canister and the filter is 60% stopped up. Any suggestions? Thanks!