I was coming home last night and my car started jerking ALOT at about 40 mph. It wouldnt go into gear (automatic) And the rpms would go up and down as the car was jerking i finall slammed on the gas and i chirped a gear and it started jerking again. Sorry for the horrible description but i dont know if its a misfire or if the transmission is going.

 

Bad Gas

 

actually it only does this when im running really low on fuel. And when im going up a hill so maybe i was just running out of gas lol.