At the beginning of last year's build, we had four working gyros. One went out last year, unrecognized, which ruined our field coordinates mode (We had a mecanum drive train). The symptoms of that dying gyro sound a bit like yours. During the build this year, we've lost two more. We now have one working KoP gyroscope, and it's in the bag. We could not find a "drop-in" replacement online, so instead we've ordered some
3-axis I2C gyroscopes from Pololu. It's on a closeout discount, but being replaced with a compatible upgrade. They had 189 until we ordered 20. We'll figure out how to use them on our practice 'bot next week.