My partner's A2 (we are 2 A2 couple!) has a problem where it occasionally goes into limp mode up hills. I read all the posts and found a split intercooler, which I replaced and I thought had solved the issue...but today she reports it's done it again! I have visually inspected all the little pressure pipes but can't find any splits. Is there a way of pressure testing the system? I have an old kit with a tyre valve which plugs into the intake pipe but where do I block it off to hold the pressure?