Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
Whats the full model number of your logitech webcam?
And what type of non syncing issue did you have previously, please describe it. And please describe what you did to fix it.
Also, is there a specific program or app that you are using the webcam with when it "jerks", such as Skype, youcam, etc?
Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.