1999 Mercury Mystique Heater Blower Motor

The blower motor does not come on all the time. You can tap the bottom of the motor and it will make ticking sounds then start running for awhile. Sometimes it runs all day and other times when you hit a bump on the road it will go out. If you tap it again it sometimes will start running again. Pulled the motor and the squirrel cage is clean. I am thinking the motor is going out? Am I correct in assuming so?