How can I find which are the weak pages pulling me down?

Hi, from my website's ~700 articles a number of them are very good articles which bring in good compliments and Adsense income and traffic and a number of them I imagine are not good enough so they must be dragging down my website as a whole so how do I find which articles are not good enough so I can edit them, improve things, add more interesting content, more pictures, etc.

The reason I think the above is because my website was doing great before October update of Google and after it crashed. Now I am recovering it still slowly by fixing crawl and other website errors, better internal links, building some backlinks by publishing articles on other blogs, but it is not where it was still, so I must have some bad content I assume as I never did any bad quality things like lame mass links, etc. and I remember I read or saw somewhere from Google saying that any bad/wrong/error pages will bring down the whole website's performance, which does make logical sense.

So how do I find those bad pages? the pages which Google might consider as bad quality?

Thank you!

P.S. I originally thought this would be pages which get no traffic, but when I took the list of no traffic pages from Analytics they included some great articles, which probably get no traffic due to very high competition on those topics and not because they are bad pages.