Electric furnace works fine sometimes at other times it acts like its hung up and if I tap the housing it starts working. It is 19 years old is it time for a new motor or is it the condenser?

Capacitor for the motor would be a cheap start.

Replace it with a magnetic field motor instead of copper wound motor. Just match up the horse power,voltage, rotation , amperage, diameter and the way it is mounted plus shaft size. Magnetic motor is more efficient

I'm with Abu65 capacitor is cheapest way to start..

sometimes the rubber tubing ends rust and drop a small plug of rust in it, during the summer and needs cleaning and the back pressure sensors work, clean all the electrical connections for corrosion.

Could be the points not closing on the motor . If you are handy . And the motor is open, give it a small shot of wd 40. The points close by centrifugal force , might be dried out and gummed up. A couple of drops of light oil on the bearings , will help as well.. old 243

Sometimes I have to blow drain tube back into furnace to get water to drain and heat to start