[V8] occasional bogging, stalling irregular idle... (when wet)

[mfjr at pro-ns.net]

Hi all,

Whenever it's raining, snowing (slushy consistency) or after I go through the
car wash, problems arise!?!?!?
 
At first, it seems like it is starving for fuel, it will idle between 500-750
rpm (bouncing back-and-forth) before finally stalling..???  On the highway
(snowy/wet conditions) it will start bogging out while trying to hold a
constant speed..  I can get it to clear up if I pump the gas vigorously, then
it's ok for a minute or two (sometimes longer) then right back to bogging and
such..

Anybody have input on this, or better yet - want to take her off my hands.. 
Would let it go for $2500 firm..  A ton O' new stuff within last three years..

Mike