Welcome to WebmasterWorld Guest from 18.104.22.168
On site we have made lots of changes.
1. On 18th June i made thousands of inner pages noindex.
Major changes to internal navigation can trigger this sort of penalty as easily as suspicious back links and I suspect that in both cases the answer líes in the anchor text.
We get rid of links google found in last two months.
Why did you give those pages a noindex robots meta tag in the first place - that is, why didn't you want to see them in the search results?
...my indexed pages have gone up three times after putting those listings in noindex...
Rolling back and carefully adding one change at a time, slowly and systematically and monitoring the results really is the way to go if you want to get this lifted.