Jerking while picking up speed

I own Hyundai Elantra 2006. Recently I noticed the car jerks slightly while picking up speed (between 0-20 and 40-45 mph). It does not happen at higher speeds, and I have no other symptoms. Does anyone have an idea of what it could be?

Have your tire's checked + speed balanced.

Have your tire's checked + speed balanced.
It was done recently, and all good.

I have the same problem exactly with my 2007 Elantra. I have also noticed that if my car is just gliding at 10 km/hr in busy traffic for more than 25 seconds, my car sometimes stalls on me, and i have to start the ignition....

does anyone have the same problem?

In my case, it was just bad gas, or dirt got in.