Car has mild bucking when reducing throttle

[edlinde]

This problem occurs at speed (above 50 mph). While trying to maintain speed on a down hill section of the hi-way, I reduce throttle pressure and the car experiences a mild bucking. The problem goes away if the throttle pressure is removed (take foot off gas). This problem occurs in moth manual and cruise control modes. Any ideas of what is causing this?

 

[scottdk]

This problem occurs at speed (above 50 mph). While trying to maintain speed on a down hill section of the hi-way, I reduce throttle pressure and the car experiences a mild bucking. The problem goes away if the throttle pressure is removed (take foot off gas). This problem occurs in moth manual and cruise control modes. Any ideas of what is causing this?

Possibly TPS (Throttle position sensor) Could you indicate which year your Genesis is? this would provide the transmission your car has 6 speed vs. 8 speed.

 

[edlinde]

It is a 2009 with the 6 speed transmission.

 

[Mark_888]

There is a TSB that affects early 2009 models where the rear axle makes a scrapping noise typically at about 40-60 MPH. Not sure if that is your problem, but search this forum to find more details including TSB number, and manufacture dates affected.

 

[Gunkk]

An old Accord of mine used to do that -- had to do with the torque converter not being able to make up its mind whether to lock or unlock when going down hill with some input on the throttle.

 

[bradyb]

An old Accord of mine used to do that -- had to do with the torque converter not being able to make up its mind whether to lock or unlock when going down hill with some input on the throttle.

I've gotten the same issue. I chucked it up to the xf programming i regards to the torque converter. It's not really bothersome...