My car seems to jump sometimes at highway speed, how do i know if this is a misfire or a surge or what?

it fells like the car hiccups or somehting, or like the is slipping, but any other time i have zero issues with the , clutch etc.. it is idling a little low, but seems fine, no check engine lights on, fluids are good. any ideas? i want to look it up but don't know what to call it, i don't ever notice the rpms cuz it is random and takes me by surprise, i'm never looking at the dash, so weird.