Here is an oddity on the GTO:
Go to start it, and just get a loud CLICK from under the hood. Doesn't start, but all accessories function and it goes through the system check and doesn't say anything is wrong.
After a few attempts, it will start. Once it does start, it doesn't have any trouble starting after that until it has sat for at least 6 hours.
It did get a new ignition, but that was almost a year ago.
I'm stumped on this one, gents.