Audi A4, 2006 convertible : after driving the car 12 miles in stop and go traffic on a 2 lane street I noticed smoke coming from under the hood, not a lot. No warning lights on the dash. Temp outside was 75. So I drove another 2 miles, then I saw a lot of smoke coming from under the hood - I turned on the turn signal to get into the other lane and then the coolant low sign came on the dash. Then a lot more smoke. After letting the car cool in a parking lot, I added the coolant/water mix as called for in the service book ( had the staff at oreilly auto parts look up the correct coolant). As soon as I started the engine all the coolant ran out. I called the tow company to tow the car to the service station. It appears to be a cracked valve. Also 3 radiator hoses all need to be replaced. The car just had a full tune up 2 months earlier.

- Sammamish, WA, USA

The vehicle suddenly and unexpectedly loses power while merging onto the interstate. Power loss generally lasts for approximately one minute. Power loss is continually experienced while attempting pass other vehicles. On occasions, the vehicle goes into limp-mode, making it difficult to maintain highway speed.

- Bowling Green, KY, USA

I have had a continuing problems with my 2006 Audi A4 quattro 2.0 with acceleration while pulling out unto a highway. The vehicle bogs down in front of traffic oncoming traffic. My private mechanic provided me a bulletin on the problem. The Audi dealer has failed to acknowledge a technical service bulletin regarding abnormal camshaft wear and failure with the standard stock factory installed pumps which are from a design flaw. The company has refused to take corrective action. The NHTSA has three items#10024427, 10030593 and 10025965 regarding issues with the fuel system. In checking online with a google search, it appears many 2004-06 Audi's have the same issue which create a danger to the driving public. The tsb is not making Audi look into the problem and I feel many consumers are planning to make repairs for Audi's design flaw including their cover-up of the design flaw. It is critical that this issue be investigated before someone is seriously injured. The consumer stated the check engine light has been on for the majority of the time he has owned the vehicle due to problems with the fuel system and or the ignition coils. Numerous times, the vehicle has failed to accelerate properly. The vehicle was taken to the dealer and upon inspection the technician noted an oil pressure issue involving the cylinder head, bearings and short block. The consumer believed the additional problems were due to a defective camshaft. Updated IVOQ 08/19/10 updated IVOQ 10/18/10 the consumers mechanic noticed metal shavings in the oil when performing an oil change. The check engine light periodically flashed and the engine did not run smoothly. Updated IVOQ 01/12/11. The consumer also stated there were problems when accelerating from a stop which may cause an accident. Updated IVOQ 02/09/11 updated 05/25/11

- Marlron, NJ, USA

The contact owns a 2006 Audi A4. While driving 35 mph, the contact noticed smoke coming from the front and back of the vehicle. She pulled the vehicle over and turned off the ignition. She then heard a loud explosion underneath the vehicle. She exited and noticed flames underneath the vehicle and from under the hood as well. When the fire department arrived, the front half of the vehicle was completely engulfed in flames. The fire was extinguished, but the fire department was unable to determine the cause of the failure. A fire report was filed. The contact did not notice any failures prior to the fire. The vehicle was inspected by an insurance adjuster, who was also unable to determine the cause of the failure. The vehicle was labeled as destroyed. The contact is in the process of notifying the manufacturer. The failure mileage was 33,000.

- Los Angles , CA, USA