Vibrating water lines

I read in this forum that the main cause of this is air in the lines well I turned off the main like it said and drained all the water in the house. Turned water back on and it stopped for a little while, but it’s started back up. It only does this when flushing one of the two toilets and sometime when the washing machine is filling, it will not do it in the bathtubs or sinks. How would air be getting back in the lines if that is the problem. I flush the toilets about three times and no vibration at all after I did the cut off thing, but then it’s vibrating again not. I did it again and the same thing, stopped a couple flushes, but back to vibrating again.