Am I fighting against myself?

I have a website having 3 different pages targeting same keywords, all these pages were made for different purposes like for SEO, PPC and other specific goal… but now the characteristic these pages having are as follows:
• All having indexed in google
• All having unique content and metas but certainly targeting same keywords
• All having different url extension
• Age of pages are significantly different (one is 2yr old (PR 4), other one is 1 yr old , one is 2 month old)
SERP behavior is like this:
• Ranking for targeted keyword is 80 – 120 varying over 2 months.
• Sometimes show one out of three (I have noticed all 3 pages at some point of time)
• Some times show two listings together (2 out of 3 pages)

Now question is :

Am I fighting against myself???
What is the probable solution???

I want to remind you that keywords are highly competitive.
Any or all suggestions are welcome and desperate.

Half thanks in advance & half after solving problem

The answer to your question lies in your resources. Do you have the time, money, and dedication to optimize all three pages? If you do then by all means keep going the way your going. But if you decide you only have time for one, or that you would rather have one really great page then 3 good pages, then you might want to consolidate. If the pages are truly related, and use the same keywords, you could do some 301 redirects to your oldest domain and boost it up, then focus on that page. I need someone knowledgeable to chime in on if it would be worthwhile to do this though.

thanks knat for your words... but having 3 pages for same keyword is the reason for my absent in top 10 results.

Your query reminds me of the question at the SEOMoz Quiz:

#24 When you have multiple-pages targeting the same keywords on a domain, which of the following is the best way to avoid keyword cannibalization?

Your Answer: Place links on all the secondary pages back to the page you most want ranking for the term/phrase using the primary keywords as the anchor text of those links

Correct Answer: Place links on all the secondary pages back to the page you most want ranking for the term/phrase using the primary keywords as the anchor text of those links

This should help you take an Idea as to what to prefer.. and thats the obvious solutions..

the source is: http://www.seomoz.org/seo-expert-quiz

Hope that helps..

thanks lovekills_s for the interesting link... but my question remained un answered as "having 3 pages for same keyword is the reason for my absent in top 10 results???".

The answer is there..you have to choose which page is most important to u from various aspects..

choose it and follow the solution.. Also, the backlinks would be the determining factor..If you are able to do so, its quiet possible, your site may acquire sitelinks..

its just that the page which is backed up by good links PLUS the more of the homepage trust, will do good..and no there is nothing like fighting against urself, its just that important pages/things comes first..depending on a lot of factors..

Make sure to find your choice of the best page, and work a little more on the links part and the above advice by Rand..