2000 Impala driveability problems

My 2000 I mpala with 142k mi will accelerate to at least 55 mph by simply taking my foot off the brakes. I don’t touch the gas pedal. I find myself having to use the brakes a lot to maintain the speed limit, even though the’t accel. is slow and gradual. Anyone else have this problem? I can’t snicker at the Yotas anymore.