91 LeSabre runs rough @ 55 mph

I have a 91 LeSabre with 170K. It's a good car so far but is starting to cough and run rough when accelerating from about 50/55. It runs great at any speed but only when trying to accelerate. Any suggestions out there? Thanks

Have you changed the fuel filter? Checked the fuel pressure at the fuel rail?

The engine will use more gas when accellerating in that range, until the torque converter locks and the engine is in full OD.

Coughing and the engine surging is usually related to a fuel problem in my opinion.