I also have a 2004 Colorado and have the EXACT SAME SYMPTOMS as like2Ride above. I’m thinkin’ it’s a computer issue or a connections issue. Seems normal at the dealer and unless I’ve been doing lots of stop-and-go activity. Once it cools down (15 mintues to an hour)… cranks normal again.
By the way… just for clarity… starter spins great… when it’s acting out, engine behaves (if you’ll pardon a term from my old, old Studebaker days) as though someone has disconnected the coil.
Now to see if I can find more about the passlock or cleaning connectors.