I bought a Q7 7 months ago its now just reaching 90000 miles. Within the past month two of the injector holding bolts have sheered off and the injectors have come out.    1 bolt I can understand that there is wear/vibration that will eventually weaken and snap but 2 within 1 month is a little hard to understand. Any ideas on if there might be a separate problem that is causing this to happen? Is there anything inside the piston that could cause that amount of force to rip the injectors