I have a 2001 Nissan Xterra and the light flicker and abs light flickers when i hit bumps in the road what could be the problem?

It sounds like a loose ground wire, which one, I can't tell you. If its in the dash, there are ground wires connected to the car frame. You probably find it by looking under the drivers dash. It will be a wire connected to the frame by a screw or nut. Just tighten it up, and should solve the problem. also check the power plug to the gauges and make sure its tight. Best I can do.