Jeff O gets the booby prize for closest guess
When removing the right header to gain access to the starter bolt it was necessary for me to remove the right-bank plugs. when removing #5 a gush of clear water came out the hole. It would seem that rainwater (intermittent problem) was running down the hood seam and into the throttle body. Thank goodness I got a good seal on the piston rings, no milky oil. Hope you had fun...it took me 6 months,a little luck, and a new starter to figger this one out.