Ken,
I realise this thread is quite old, but thought i’d put my two cents in.
This may or may not help. It is (still haven’t fully diagnosed it) the major source of my speed problems. https://www.devdawn.com.
In your theme’s header.php file (i used K2), you should see a call to wp_head().
This is the function that I’ve removed from is_home(), and kept for all the others. If you watch how fast the home page loads as compared to the sub-pages, it’s quite a margin.
From my recollection (I’m about to undertake more serious diagnosis right now) it’s got something to do with how many times wp_head() (or functions underneath) access the database.
Will report back if i get it fixed.