Quoted From EricTheCarGuy:
If it’s a manual then it may be a problem with the clutch, if you don’t find a performance issue with the engine it’s probably not a bad idea to check the clutch operation.
http://www.youtube.com/watch?v=h7JJ_g2UuBI
Checked the video, definately not a clutch problem, it has none of that slipping when changing gears, and if i would lift up with a gear in it would either take off or stall for sure.
It’s more of a very rapid jerk/misfire, split second and then back to normal, but now it’s been going for almost 200km without one single incident.
The kia place i went to didn’t even think it was worth taking a look at, suggested i come back if the check engine light came on or it was happening ALL the time, basically no check engine light and rare intermittent problem = many many expensive hours to find the problem (at ~200 USD an hour, 1500 SEK).