I was going up a couple hills at 60 mph and felt a quick jerking from what felt like the front wheels. The tach didn't move and I didn't hear anything in the drivetrain. I talked to a friend with the 3800 in a Regal and he said it could be a crank position sensor. Talked with somebody else that said fuel filter change, but that would cause the RPM to jump around so I don't think its that.
There is a slight chuggle that happens on my 96 when going up hills between 45 - 50 MPH.
If thats what you mean.
Seems to happen when the fluid gets hot and thin. Its almost like an irregular acceleration when the car is in lockup.
Search the 92-99 section and you will see posts on this.
I'm still new to the BC but I did experience the same jerking between 40 and 50 MPH. I took it to the shop and my mechanic actually determined that it was the MAF sensor. He told me that he actually worked on several bonneville'* that were jerking and it was the same exact thing. I previously changed my plugs and wires though so that may have had something to do with it.