Question about post being d-indexed

Ok, not sure why this would happen. We'll, I think I might know, but not exactly sure.

Anyways, I had a post that I made last Friday Night, and on Saturday and Sunday I was turning in some good traffic. On Saturday, had over 1600 hits to the post, and on Sunday, over 1300 hits.

Sunday, I was looking at Goooooogle Webmaster tools, and it showed that post as being indexed, etc. I was typically in the top 1 - 3 slots for the search terms.

Then, I went ahead and did two things, which I think one of them is why it's not showing up anymore.

I saw the terms they were searching for, and started placing more of them in the post, and also using the <strong> tags on them.

Then, on Sunday, i was actually updating my post, kinda adding stuff, making some of the post <h2> , etc, etc. Instead of using the "preview" i just kept hitting "update post". Then refreshing the page to view the results. I heard that could get you marked as spam, after researching it yesterday.

Roughly all my other post are indexed, and doing fine, except for this one post.

So my question is, the two issues I did, would that cause the big G to d-index that post, if

1. I used to many keywords in the post
2. Updated the post to many times in a short amount of time

Thanks guys for all your help on this

NUmber2,see my thread before but i get my blog index again.ahhahahah
i have already know about autoblog...deindex is okay ,banned is F*ck

yeah, I wasn't even using autoblog though. I actually came up with my own content.

NEVER submit your autoblog(spam, doorway, cloaking site) to google sitemaps, srly, NEVER, is only useful for WH, for BH is big NO