I have a similar situation. Just replaced struts due to a bad drivers side spring. Installed monroe quick struts... twice because I thought it was a bad assembly. I have been chasing this fast knocking noise for a month now. I was a technician for 13 years. Let me tell you... I AM FRUSTRATED!!! So, I found my passenger side forward control arm and ball joint assembly was popping and squeaking... replaced it. So far the struts I replaced (twice), forward control arm ball joint assembly. I se No movement in anything else. Went as far as disconnectin the sway bar link... no change. I am ready to set this car on fire.