Manifold/Fuel Pressure Gauge Failure

[Brad1998]

So today on the way home (Pa) from Penn Yann NY I discovered the Manifold pressure gauge had failed. I started pulling throttle back after takeoff and the MP stayed at 30 Lbs at about 1-2000 ft and at 5,500 ft it was at 25 Lbs. The fuel pressure side of the guage was also not working. I took a few friends up 2 hours prior to the flight home and everything was working correctly.... Is there a possibility it could be a plugged line? or is it more likely a guage failure? Thanks