After a long (several hour's drive), I exited the expressway, and was waiting at a stoplight. When the light turned green, I pressed the gas pedal to accelerate. I heard the engine rev up very high, followed after several seconds by an extremely hard shift, which made all of the occupants of my car think we were rear-ended. After that, the car seemed to run just fine. There was no visible damage.

On numerous occasions after buying the car new, I would feel a shudder during braking to a stop. It feels as if the car is attempting to shift into first gear instead of stopping. The car has never stalled, and I have never felt as if it weren't safe to drive the car, but feel that it is worth mentioning. This has probably happened a dozen times over the last 6 years and 53000 miles that I've owned it since new (the car doesn't get a ton of use).

After the incident I mentioned first, and after each of the shuddering incidents, I would put the transmission into manual-shift mode, and I have felt no issues. As such, I don't believe there are any mechanical issues with the engine, flexplate, torque converter, or transmission. I suspect that the problem may be computer related, although from reading about other owners (of CX5s), dealers flashing the computer are not resolving the issue.