On my wifes 01 ford focus se with the 5 speed
First problem. I have an engine light that has something to do with o2 sensor heater circuit but i just replaced both sensors so I ask what is this all about and how do I fix it?

Second:while driving the speedometer wil stop working and go to zero and the mileage won't increase on the odometer. Then for whatever reason it all comes back on and everything is good. Any ideas?

You've got a wiring problem. A 02 sensor code doesnt mean the snesor is bad, it means there isnt a good signal getting back to the ecm. Or the heater circuit is bad. Either way, you will need to check the wires going back to the ECM. Same thing for the speedometer/odometer problem. Both are controlled by the same sensors. You have a wiring problem. Has the car been in an accident? Or has sonething been done as far as modifications?