Car started in garage with garage door only open a couple feet. was on for 5 or so minutes before driven. 2 hours later feel ok. risk or co poisoning?

No worry: Yes, you are correct. That was an "at risk" situation. However, if two hours have passed with no headache, dizziness, confusion, fatigue, or nausea, you should be fine. Never ever run an automobile or other combustion engine in a poorly ventilated area.

Unlikely: usually need more exposure to do sig harm....if you remain fine as you are now, I wouldn't be that concerned, but if you start to fel worse, then see your doc for evaluation.