NHTSA Complaint #10285091 — 2004 AUDI A6

I HAVE A 2004 AUDI A6 2.7T S-LINE SEDAN WITH 56,000 MILES ON IT. FOR THE PAST SEVERAL MONTHS IT HAS HAD A SEVERE SHUDDERING IN THE STEERING COLUMN AS I ACCELERATE MID-THROTTLE, AS WHEN I ACCELERATE ONTO AN ON-RAMP. I HAVE TRIED TO HAVE MY LOCAL AUDI DEALER ADDRESS THIS (IT IS A CERTIFIED VEHICLE) BUT THEY SO FAR HAVE NOT COME ACROSS WITH RESOLUTION. I HAVE ALSO CONTACTED THE AUDI OF AMERICA CUSTOMER SUPPORT FOLKS SEVERAL TIMES AND THEY SAY THAT THERE IS NOT A PROBLEM LIKE THIS WITH THIS CAR, BUT THEY ALSO SAY THAT IF I USE A SPECIFIC MAKE OF MICHELIN TIRE, IT MIGHT ALLEVIATE THE PROBLEM! I'M CONCERNED ABOUT THE SAFETY OF THIS CAR-IT DOESN'T ALWAYS DO THIS, BUT WHEN IT DOES THE STEERING WHEEL "SHUDDERS", LIKE IT VIBRATES/WOBBLES AND THE WHOLE CAR VIBRATES. IT STARTED AT ABOUT 40,000 MILES AND SEEMS TO HAVE WORSENED OVER TIME. IS THERE A COMMON PROBLEM WITH THIS VEHICLE? PLEASE HELP IF YOU CAN! *TR