Mid session load makes game laggy

I was in the middle of practice and needed to stop so I pulled into the garage to save the game. I left and came back loaded the save file and in the garage everything is fine. Went out onto the track and when the AI was driving everything was fine. Then it gave me control and it became extremely laggy and stuttering. My fps went from 86 to 5 and my micro stutter rate went up to 100%. I only had one more program in practice so I finished it and went to Sprint qualifying and its just as laggy. 80-90 fps in the menus replay video and when AI is driving but as soon as I take the wheel its drops to 4-5 fps with 100% micro stutter rate. Attached is a video of the game running fine in the menu and when AI is driving then losing it when I take over.