1996 Chevy Beretta oil light question?

My wife has a 1996 Beretta w/ 100,000 miles on it. I'm very confuesed. It seems like every time you hit a bump or stop at the bottom of a hill all the lights go wacko. The oil light will stay on for a few seconds and the car will want to stall out, But I just throw it in N and give it some gas, then it's fine. Until I hit another bump. I cleaned my battery cables, tightened them up, changed the oil ond filter, also put in new plugs and wires. Does anyone know what else to do befor I take it in.