Renault Megane II combi 1.9 96kw

[nwmcz]

Hi, I have a Renault Megane II estate 1.9 dci 96kw, and while driving, the car randomly jerks and displays messages on the dashboard asking me to press the clutch or brake and the start button. This happens regardless of speed and even when the car is stationary with the engine running. Has anyone encountered this issue and knows what it could be? I've tried many things and am out of ideas (diagnostics show error DF312, which I found on a forum suggesting that a DPF regeneration is needed, but this can't be completed because the car "jerks" and sometimes the engine shuts off on its own). Thanks to anyone who can provide advice