service engine soon light and when you try to take off it feels like its in 2nd

Generally trouble codes just tell you what system in the vehicle has a malfunction - Many times people will guess as to what is wrong & just start replacing parts. The best recommendation is to find a facility that can properly diagnose the car & then let you know what needs to be repaired. The code P0780 generally relates to a transmission fault & could be an issue with the transmission itself or one of the many electronic devices that control the transmission.