I posted something a while back about my ac coming out of the windshield vents and was told to check for vacuum leaks. I was wondering if there is a certain process for this or a link w/ vacuum diagrams etc. I have been noticing a deisel fuel small when starting my truck. Any ideas on the cause

 

If it is a 4X4 it may be in one of the lines to the hubs a common problem.
You may have a leaking fuel bowl drain the o-rings for the drain is another common problem.