Is there something loose with a fan blower on a 1994 Olds Achieva if sometimes it works and sometimes it does not and at times when it does not if it hits a bump in the road it blows again?

The blower motor is worn out. My 95 Achieva had the exact same problem and I had the motor replaced. It cost $168.00. $70.00 for the motor and the rest was labor. I had the same problem in my 92 Achieva S. I agree, the blower motor is going bad. I bought a rebuilt one for $30.00 and installed it myself. It is easy to do.