1989 Cutlass Supreme. Going down highway and the car losses power. Feels like its running on 2 cylinders. Replaced MAP sencer and still does it. Any ideas

In 2008, I had a similar problem with my 1988 Cutlass Supreme during a road trip on Interstate 70, stranded for a day. The digital display started flickering and a few seconds later the engine quit. The problem was a poor battery connection. Apparently, the alternator feeds power through the battery connectors, so keeping the contact surfaces clean with a soft wire bristle brush is necessary.