Anyone have this problem?

I have two speed sensors to check with and they both come up with the same results. This mostly happens when the car is hot. It doesn't always happen though, but I do have to keep my rad fan turned on while driving. Sometimes it'll go crazy and read 120 mph when i'm going only 75-80. Or else it'll just die and won't read at all which of course, will throw a code, speed sensor.
If you have this, what have you done with fix it?