Mk2 octavia vrs p2196 engine fault code

Having issues with the p2196 engine code. Code reader reads bank1 stuck so had it replaced today by a garage and its clearly new but after 30 miles of her eating fuel like ive never seen before the engine code has come back on with the same code. Only had the car 3 months but it has got egr and dpf delete so could this play a part into why this code is recurring or could it be electrical issue. It definitely has electrical issues as it tells you to check numberplate lights that are clearly working and every now and then the lights flickering when not turned on. Need help as she's thrashing my head. Thanks