So today a code popped up after the other half did the school run. P023D, and it happened coming up a steep hill out of a 30 at moderate throttle. Popped the bonnet and found a boost pipe which had a small split in. No noise and I’m not even sure it’s split right through but I know hoses can cause this code. What I did notice is the air flow meter values. With ignition on and engine off bank 1 was showing a bike compared to 2 which was at zero. At idle bank 1 showed 38g\s and bank 2 was reading 10g/s. I’d expect a closer reading. On road test it didn’t fault but the air flow is wildly different between the 2 banks.

New hoses fitted and 100 miles covered today, no issue. I also cleaned the map sensors and throttle response has improved along with average economy upto 35.7 mpg on the journey to work and back.