Dispersing pagerank within site

Dynamic pages sucking up pagerank?

[Decius]

I have a dynamic site with lots of internal pages that are not likely to result in anything unique in the SERPS, so there is no point in them being indexed.

My question is, are those thousands of internal dynamic pages stealing pagerank from the main /index page?

If I use the "noindex,nofollow" meta tag, will google ignore those pages and not disperse pagerank amongst them?

Is this likely to alter the weight the main pages of my site receive?

Thanks.

[Decius]

Does anyone have any input on this question?