My TL-S has a tendency to produce a bucking while cruising at 50mph. I used to think that it is the transmission, but maybe it is the engine cutting out because the computer tells it so? It always happens when I am cruising at 50mph, not accelerating, not braking. Just trying to stay at 50mph. It usually bucks only once.

 

I've noticed some slight bucking at or around that speed as well. In trying to reproduce it, I've come up with the following theory:

50MPH is about where the transmission will upshift to 5th gear, although it's below 1500 RPM. When you try to accelerate slightly (very mild tip-in throttle) it's not enough to downshift (or even unlock the torque converter) so it's trying to pull the car forward from 1500 RPM in the tallest gear which doesn't always go over well. I've had this happen 3 or 4 times and if I try the above method I can usually reproduce it.

 

Hey RAdams, I just noticed you are in Hollywood, FL.

Maybe our Acuras are affected by warm Florida weather? Or high humidity?

 

It's probably the torque converter lockup mechanism. Cruising at 50 mph in 5th gear is probably right there in the torque lockup threshold.

When you're cruising on down the road and the torque requirement is low, the computer locks the two halves of your torque converter together and your RPM drops a little (about 200 to 500 RPM drop), and you gain fuel economy. But when you step slightly on the accelerator, the computer senses that you need more torque and releases the lock. RPM surges up again by about 200-500 RPM until you relax again, etc.

Is that what you're experiencing?

 

I'm very familiar with torque converters and my best guess is that the bucking is due to the converter NOT unlocking when we demand a little more power (i.e. pressing lightly on the gas pedal). If it did unlock, the RPM would raise by a little as you stated but the transition from coast to accelerate would be much smoother than what we're experiencing.

 

mine feels like the engine cuts out (something I have experienced in SS when in redline)