Dear friend,
1. Panda = "Pour quality content" usually duplicate content with other sites or pages with small amount of content.
2. Penguin= "Unnatural Links "
If you suspect about 1 and 2 try to work hard to resolve these issues first.
... And later check other things, I have some sites with very pour html and great content and natural links and they are ranking great.
Remember the Google recommendation "useful content for visitors= more external links (votes)" which means high quality site.
Hope it help