Citroen DS4 jerking at low rpm in 2nd gear

Vehicle can boost now after I replace the electrovalve( all or nothing solenoid) runs fine at higher speeds. It will jerk mostly in 2nd gear at a low rpm till the turbo kicks in. I also hear a bit of detonation at low speeds when accelerating. I remember changing the fuel filter primed it with the built in primer but found that one of the fuel pipes were not pushed in properly which made it a nightmare to start. Currently the only DTC on there which doesn't go away is P11B2- Measurement of the EGR exchanger bypass, short circuit to positive.