Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 1999 Audi A6 owners, lightly cleaned up (personal details are redacted by NHTSA).
On the morning of November 20, 2010, I was pulling in to a parking space at the local library, approximately 10 minutes from my home. As I was making the turn to pull into the parking space, I heard the engine rev, and the car accelerated as though the cruise control had "kicked in" and my brake would not stop the car. Rather than hit a car that was parked in front of my parking space, I turned the vehicle to go up a curb and hit a tree. Once the tree stopped the car, I was able to put the car in reverse, back down off the curb, put the car in park, and pull out the key. Oil was pouring out of the vehicle and it had to be towed to my home, was examined by my insurance company, and was written off as a total loss.
While driving 60 MPH on the freeway, the car accelerated on its own to 72 MPH as if going into cruise control. Confirmed the cruise control switch was turned off. Applied the brakes seven times. Car did not respond to braking. Engine seemed to race against the brakes. I put the car in neutral, moved to side of the road. Applied the hand brake. Turned key off. Car slowed then stopped. Since this incident the car was test driven twice by mechanics, during which it seemed to operate normally. On January 27, 2015 the car was taken to the local dealer, bellevue Audi, for diagnosis. Awaiting results.
Consumer's wife had a bad experience last month with the cruise control. She had the cruise set at 75 MPH and hit the brakes to turn off the cruise control, but vehicle did not respond. She turned off the switch on the steering column, and that did not stop the cruise control. She put both feet on the brakes and tried to stop vehicle, but the engine continued to run. Fortunately, consumer was able to power brake the vehicle, and bring it over to the shoulder of the highway. Then, brought the speed down enough to slam the transmission into park, and abruptly stop the vehicle's motion. All four wheels were smoking, and she turned the vehicle off. She called the maplewood Audi dealer, where consumer had the car in for full service and scheduled a checkup. Vehicle was towed to the dealer, and kept for diagnostic investigation by the technician. …
Tl*- the contact stated that the 1999 Audi A6 quattro had problems with acceleration. The vehicle accelerated on 02/05/07. The contact's wife was driving at 65 MPH when the vehicle accelerated on its own. The contact stated the only way the vehicle stopped was to push the brake pedal with both feet. The contact called the dealership and had an appointment set up for today 02/12/07. It happened again on 02/09/07. While driving the vehicle, and she was at a complete stop made a right turn and slowly accelerated to 45 MPH. The road surface was completely dry, the vehicle accelerated unexpectedly. The gas pedal went to the floor by itself without her pushing it to the floor. The driver applied the brakes with the right foot and the vehicle didn't stop. Then tried to pull the accelerator pedal up with the oe to stop the acceleration. …
Car: 1999 Audi avant wagon 1. The car was left outside during the winter of 2008/9 and unused for several months. In sprint of 2009, the car was jump started and this is when the problems started occurring. 2. Regardless of cold weather, the car will accelerate. More specifically, when the gas pedal is released, the car will not decelerate. This means the car will propel itself forward. Without depressing the gas pedal, the car will sometimes achieve a speed of 40-45 MPH. By pushing the pedal down and releasing it quickly (pumping the pedal), the throttle will release and the car will come back down to idle speed. This occurs not every time but approximate 1 out of 10 times that the car is driven. 3. The tube that leads to the throttle, the accelerator cable, and the throttle body have all been replaced. …
For the past several winters, my 1999 Audi A6 2.8 quattro has had a failure in its cruise control mechanism. When ever it gets cold the cruise control often does not engage, and if it is really cold it May disengage after running for awhile even on level pavement (I.e. Not undo engine strain-normal for disengagement). The major problem lies in that, at least twice, even though the cruise control has not been made to engage on prior attempts, it has engaged latter on its own, without prompting, bringing the car up to speed. Case in point: one time when coming into a residential area, it suddenly engaged, and started to try and come up to highway speeds. The dealership has tried several attempts to rectify this fault, but has been unable to find a solution. I have even offered to drive my car up to their national headquarters for their engineers to look at. …
Driving home tonight my car all of a sudden started accelerating (I drive an Audi A6 1999). Using the brakes I was able to slow it down enough to get off the freeway though my brakes seemed to be fighting against the car. I rolled through two stop signs as my car would not stop and luckily avoiding the other cars waiting there I was able to put my car in park and turn off the engine. I waited ten minutes or so and tried starting my car. The engine revved to 4 to 5000 rpms so, I quickly shut it off again. I waited again, tried it once more and the car started fine. I drove home, called the dealership and was told I could be seen on 02/14/11. Four days from now. This is the second time this has happened.
Throttle stuck. It happened during sub zero weather while consumer was driving about 70 MPH on a highway. Consumer had to use both feet on the brakes to pull over. When consumer put vehicle in park it red lined. Consumer shut vehicle off , and turned it back on without any problems. Then, dealer looked it over, and said they couldn't find any problems with the vehicle.
The throttle stuck on my '99 Audi A6 2.8 quattro at 70 MPH on interstate I-65 in indianapolis, in. It took both feet on the brake to stop the vehicle and still almost hit someone in the rear (scary). I put the car in park, it red-lined and I turned off the ignition. When I restarted the car the throttle had reset. Fortunately my wife was not driving.
On a below zero day the throttle on my 1999 Audi A6 quattro was fully engaged after lifting off the pedal. Car was stopped only killing the engine via the ignition. Vehicle was restarted and problem continued. After jostling the pedal and restarting vehicle was fine.
Related recalls
Vehicle speed control
On certain passenger vehicles equipped with 2.8l, v6 5-valve engines, and automatic transmissions, while driving during extremely low ambient temperatures the throttle May freeze in an open position due to ice accumulating in the throttle body.
Remedy: Audi will install a replacement throttle body kit free of charge. The recall began on October 29, 2004. Owners May contact Audi at 1-800-822-2834.
NHTSA investigations
Fuel expulsion
By letter dated March 22, 1999, Volkswagen notified NHTSA that it would take safety recall action to correct the spitback problem on all the subject vehicles.based on the manufacturer's recall action (odi 99v-058), this investigation is closed.
Acceleration complaints in other A6 years
Frequently asked questions
How common are acceleration problems on the 1999 Audi A6?
NHTSA has 24 complaints about the speed control & acceleration of the 1999 Audi A6, 11% of the model year's 217 complaints. The component named most often is accelerator pedal (7 mentions).
Is there a recall for 1999 Audi A6 acceleration problems?
Yes — NHTSA recall 04V-495 (vehicle speed control, Oct 12, 2004). Recall repairs are free at authorized dealers.
At what mileage do 1999 Audi A6 acceleration problems start?
Half of the complaints with a recorded mileage happened before about 76,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 1 injury to speed control & acceleration problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.