Car is sputtering and jerking

My car is sputtering and jerking as I am driving down the highway after I reach 55mph. Also my gas gauge is floating. Could this be from the same problem. I do know one of my spark plugs has a miss

It Just started doing this a couple of days ago. It does not do it while I am driving in the city and when I push on the gas it has pick up still but when it is sputtering it feels like it is going to run outta gas.