I have a similar noise from the injectors but its not 100% the same. I dont want to sound wise but it doesnt sound like a knock, more like a clunk. Wobbly water pump?Check the belts and see if any pulleys are wobbling.
I had a ticking noise on my van for months and thought it was something internal to the engine. A month ago when I went to change my spark plugs, I found that the rear two were severely loose, and when I put in the new plugs and started it up, the ticking noise was gone, and has not returned since the spark plug change. So maybe you have loose spark plugs?