I have an elevator that will intermittently trip the Governor over speed switch as well as set the safeties on the car. This car will run for an unknown amount of time before breaking. Sometimes up to 3 weeks. It never seems to be in the same spot in the hoistway and the rails are lubed with no apparent binding of the car. The only common fault that I have in this elevators fault log is a 21 that appears to be my beginning fault. I can see where the Bldg owner has reset power and such from the 170 faults in the car. My other common fault is a 152 fault, but it usually occurs in the middle of the logs. Upon today’s inspection (Thurs), I had a 152 and a 170. This was reset on Monday. These were the only 2 faults. The governor has been replaced, along with the encoder. Originally thought car may have been truly over speeding. Any ideas?