I had exactly the same problem :shock:
1) check your egr valve, it might be sticking
I blanked mine off and the valve couldn't open, so I drilled a hole to allow the valve to move - but still left the other hole blanked off
2)the aircon uses a different map on the ecu and this needs to relearn the parameters, you need to drive very carefully for 50 miles or so with the aircon on 🙁
the above cured the problem 😃