The car exhibits an excessive vibration while idling. This is the 4 cylinder 2.4L direct injected model with the 8 speed dual clutch transmission. The issue began occurring about a year into ownership, around 10,000-12,000 miles. I am now at about 3 years of ownership and 30,000 miles with no fixes yet. The issue is most pronounced when the vehicle is in gear and the foot on the brake when stopped, like at a stoplight. The vibration seems like an engine/exhaust sound at a very low frequency. It is very annoying and even painful at times, especially after prolonged stops at stoplights or traffic jams. It gives me headaches from time to time. I have had a couple Acura dealers look into it. Unfortunately their diagnosis was this is normal operation.

I have even called Acura Client Relations a couple times. They escalated the issue but ultimately concluded they could not help me and the issue was an incompatibility between the owner and the vehicle. Seriously, they said that. The dealers have compared it to other used 4 cylinders TLXs and said my vibration issue was similar. I did test drive a brand new 2018 4 cylinder a few months ago and it did NOT exhibit this issue. And I am very familiar with 4 cylinder cars, as I've owed several and none of them did this. I know 4 cylinder cars have more engine vibration than a 6 cylinder, but this is bad. It happens most often if there is some load on then engine, like if the AC or heater is on.

I can mitigate this issue in several ways. 1) Avoid stopping. 2) Put the car into neutral when stopped at stoplights, etc., 3) Minimize the use of accessories. 4) Keep all the windows closed. My guess is that there is some resonance between the engine exhaust at low rpm and the chassis/cabin design. I have seen lots of complaints about the 2.4L direct injection 4 cylinder in the Honda CRV having low rpm vibration problems too. May or may not be related. I cannot believe a modern car, especially one from Acura, would do this. And it's also unbelievable that Acura Client Relations is blaming me instead of digging into the issue with the car. While the dealers have looked into the issue, there is nothing more they are willing to do. Ugh. I planned on owning this car for 10 years+ like my previous Acura TSX, but I might just need to find an automaker who I'm not incompatible with. Also note, the car is very quiet when driving, it's just annoying when idling.

Update from Mar 12, 2019: I have been researching this issue and the best I can find is that this 2.4 liter direct inject "earth dreams" engine is based on the 2.4 L DI engine also in the previous gen Accord, previous gen CRV, and the base current CRVs. This engine has a 8-mm offset between the cylinder bore and the crankshaft. This is intended to create a more favorable crank angle for improved efficiency. So much for precision crafted performance. And I still cannot believe Acura Client Relations filed this as an incompatibility between the owner and the vehicle. I'm steamed and upset Acura is blaming me.

Update from Jul 22, 2020: The started battery was no longer holding a charge and I had the battery replaced. After sitting for a couple days the car would not start, and Acura diagnosed it as a bad battery. The replacement battery fixed the starting problem, but also help reduce the vibration! Wow, this seemed very unrelated. But the best I can figure is the battery was slowly losing performance and was having a hard time hold a charge, thus the charging system was working hard and putting some extra load on the engine, particularly at idle. The vibration is now consistent with new TLX's on the dealer lot. I still think the vibration is a bit more than other vehicles, but it's better now and consistent with brand new ones.

Update from Jan 5, 2021: Just one last word on this. It does make sense that a bad battery would contribute to this as it would place a continuous load on the engine as the charging system was working hard, particularity at low rpm. I am glad this has been addressed, but it took several years and it wasn't until the battery fully died. Glad it was under warranty but I do think Acura could have been a little more interested in investigating this instead of filing it as an incompatibility between owner and vehicle. Here's some advice for Acura, if you cannot find a solution, that doesn't mean nothing is wrong. Maybe err on the side of believing your customer. Thanks.