Well, we share this common factor as well. Mine never set a code either.
A friend of mine had this same problem, except it did not always start up
immediately. Mechanics could never find the offending part. Last time it
failed him in front of a Toyota dealership, HE fixed the problem.
Seriously, there are lots of places where ground wires can go bad, or
connectors can get dirty or loose. At some point you may have to resort
to "trial and error" parts replacement, and that gets very expensive. Start
with the cheaper stuff first. (Dealerships and independent garages sometimes
have to do this too...It really tends to piss a guy off).