Hmm not sure if this is a sandbox or a dance, after following Google advice I lost my rankings

Hi Warriors,

When Google released their new Panda update my sites gained rankings, I have 2 sites in the same niche ( totally different content except for one menu and hosted on different accounts). After reading about the new update I noticed that I was using a keyword in the menu and the keyword density was 24% for that keyword, a week ago I decided to ask what should I do @ Google webmaster forums, I have been advised to remove that keyword from the menu because it looks like keyword stuffing + "they said its disrespectful for my visitors"

Example: lets say my site is about phones, so the menu has "blackberry phone , Samsung phone, HTC phone..etc" , I removed the keyword "phone" from the menu, the page that was ranking was for "phone reviews", the next day my ranking tanked big time and now I am nowhere to be found at Google for that keyword, I am using an EMD 9+ years for that keyword

All my pages are indexed and some of them are ranking at the first / second page but the main keyword is not ranking at all, as I said it lost all the rankings...

Does Google sandbox a single page? I am not sure what is going on..I am going to wait and see if they come back..I am suspecting that I should have never removed the keyword "phone" from the menus...

As I said I have another site with the same menu, that page is still ranking even tho the keyword density is 24%