In September 2008, I purchased a new 2009 Acura Tsx from an authorized Acura dealer in Pennsylvania. After a few weeks of driving, I started to notice a knocking noise coming from the engine. The noise occurs consistently while accelerating (particularly when accelerating between 2000-3000 rpms while going uphill). Per the dealers instructions, I have used only premium fuel in the vehicle since the purchase date. I heard this knocking noise while driving the car throughout the winter; however, the noise has become progressively louder as the weather has become warmer (the noise is much louder when the temperature is above 60 degrees). I took the car into the dealer (where I purchased the car) today (4/24/09). One of the technicians rode along with me, and I was able to replicate the noise for him. The technician acknowledged the noise and said that I shouldn't worry about it, that it is a normal characteristic of the car. I received a receipt from the dealer stating this in writing. Although the dealer states that this is a normal noise, it's not something I've ever heard in any other car before (including my last car, which was also an Acura) and I'm concerned that this problem may actually cause damage to the engine over an extended period of time. There are many other people that have reported the same problem on this website, and on many of the Acura discussion boards. My next step is to take the car to another Acura dealer to get a second opinion, and also to contact Acura's corporate customer service department. Any assistance the NHTSA could provide to the group of people that are experiencing this problem would be greatly appreciated.

- Wilmington, DE, USA

Engine pings excessively under load at between 2,000 - 2,500 RPM. I am running premium fuel (91 octane) as dictated by the owner's manual. This happens every time I drive the car.

- Camarillo, CA, USA

The engine makes a pinging, knocking sound about 80% of the time when accelerating. I've complained many many times to Acura but they're refuses to do anything about; I don't know what the long term reliability issues are with the vehicle but it is known that engine pinging is damaging to the engine.

- Raleigh, NC, USA

2009 Acura Tsx was purchased on 12/13 /08 in san antonio, tx. During the 1st month the car developed an engine/knocking noise when driving and accelerating. The car has been taken to the dealer a total of 3times. Per the dealer, this issue appears to be occurring on many 2009 Tsx models. The noise is consistently produced while driving and accelerating, further pronounced while rpms are between 2000 and 2700, and has become more prevalent/louder as time goes by. As instructed, the vehicle is only run on premium fuel. The dealer has been able to replicate the noise, but is unable to determine a fix. I also called Acura client services and was told that there was no known issue for the 2009 Tsx, which I find hard to believe being so many owners have this problem. However, according to the dealer, many Tsxs are experiencing the same issue and nothing can be done based on no resolution from corporate. Given Honda"S strong root in reliability, value and customer service, I find it hard to believe that this metallic knocking/pinging from an engine would be considered ?normal". I am very concerned that this knocking/pinging noise is a design flaw/defect that will develop into long-term safety and reliability issue given the detrimental impact to the engine/powertrain. Finally, due to the fact that I am just being ignored by the dealer and corporate, your help/intervention of this problem and any recommended solution with Honda Acura would be greatly appreciated.

- San Antonio, TX, USA

2009 Acura Tsx was purchased on 12/29/08 in pa. During the 1st 3 months of purchase, the car has developed an engine/knocking noise when driving and accelerating. The car has been taken to the dealer a total of 4 times thus far for investigation. Per the dealer, this issue appears to be occurring on many 2009 Tsx models.. the noise is consistently produced while driving and accelerating, further pronounced while rpms are between 2000 and 2700, and has become more prevalent as time goes by. As instructed, the vehicle is only run on premium fuel. The dealer has been able to replicate the noise, but is unable to determine a fix. According to the techline, the metallic knocking/pinging the Tsx makes while driving and accelerating is "normal at this time? and the issue is under investigation. I also called Acura client services per the case number above and was told that there was no known issue for the 2009 Tsx. According to the dealer, many Tsxs are experiencing the same issue and nothing can be done based on no resolution from corporate. Given Honda?S strong root in reliability, value and customer service, I find it hard to believe that this metallic knocking/pinging from an engine would be considered ?normal?. I am very concerned that this knocking/pinging noise is a design flaw that will develop into long-term safety and reliability issue given the detrimental impact to the engine/powertrain, causing the engine to shutdown during driving, etc. If this issue is wide spread as the dealer reports across the 2009 Tsx fleet, I am concerned of this issue and Honda's failure to address the issue or provide an explanation of the cause. The austrilian gov't is also investigating a similar issue with the Honda euro, pressuring Honda to identify the issue and provide a fix before long-term safety issues arise. " your consideration of this problem and any recommended solution with Honda Acura would be greatly appreciated.

- Malvern, PA, USA