jumping feel and sound

Anybody ever get this? I was waiting at a drive through listening to my car running and then there was this very brief jumping feel and sound. That is the best way I can describe this. Any idea what this could be and if it is anything to be concerned about?

Did your check engine light come on? If so then get the code read at a major auto parts store. If not, it could be a couple hundred different causes. You didn't give the year and engine. There are issues more prevalent depending on which vehicles series it belongs to. I'd first check for vacuum leaks.

No the light didn't come on.

It's a 2000 Taurus with 6 cylinder

I have a 2001 DOHC that does the exact same thing. I'll be sitting at a light and it'll be purring like a kitten and all of a sudden it will jump slightly and then the rythem of the engine will just change to a slightly rougher idle. No lights, comes off the line just fine, no issues driving. Always worries me, is the car gonna stall, but it doesn't so I just let it go.