Check this out.
http://www.scootdawg.net/showthread....heck+regulator
I would be checking grounds as stated above too. You ever heard of "Loose lips sink ships"? Well Loose grounds cause gremlins. Yes, I made that up realize it doesn't rhyme. But you get the point. I once chased down various problems on my powerstroke for a week to find a loose ground on the firewall. It was wreaking havoc.