Hi everyone. I have a 2003 Mazda Protege 2.0 L and after having an NC expection where they have to hook it to a computer to pass it. The check engine light then came on. We took it to Auto Zone for one of those free diagnostic test and it should multipe codes. The next day it overheated on us and my husband changed the thermostat and it still overheated. So he took the thermostat out since it is only really required in the winter but it still overheated. No leaks, fan works, radiator had no leaks so we had it towed to a shop that someone recommended to us. We told them that we thought it was the water pump. They called us after looking over the car and said it needed new thermostat, hoses, thermostat housing. All of which my husband could have changed easily. We did know the thermo was new and so were the hoses. So they fixed it and it still over heated. We finally got them to listen to the water pump and, yes, it was bad. Now overheating problem is fixed but the codes that are coming up is for other things. They called and told us that 2 sensors needed changing and wanted to charge us another $400 on top of the $700 we already owed. We said no because my husband could change them and at this point we didn't have much trust for them after the water pump issue. As I drove the car home it had no get up and go and it cuts in and out like it is missing. We assumed it was the sensors as we were told. We got a VICS Solenoid and VTCS solenoid and changed them both. Now the car is still doing the same thing. The coded that came up are P0660 (VICS Solenoid Value Circuit Malfunction), P1631 ( Generator Output Voltage Signal - No Output) and P2009 (Variable Tumble Solenoid Circuit). We have reset the computer after installing the solenoids and nothing, still the same. We also changed out the EGR Boost Sensor Solenoid valve. We are looking into possibly changing the EGR Boost Sensor. Most of these part are so expensive and they are factory. We are sinking in debt over all of this. My hopes are finding someone here that can give me some thoughts on what it may be or if you have been through this same thing. Thanks so much and I thank you in advance! We really do need help PLEASE!

 

That's a little too much for a comprehensive answer.
I think you are approaching this from a wrong angle. Codes don't say bad oxysensor, replace it now! Codes say that the data from this sensor or that sensor are out of range and please look why that happened.
Clean the throttle body with throttle body cleaner , take out and clean the EGR valve, Replace all those vacuum hoses, it's cheap enough. Make sure the nipples where the hoses connect are not clogged. Give it new plugs, wires and maybe a coil pack and use gumout fuel system cleaner a few times.
If the overheating persists check for a leaking cylinder head gasket.