You might have a different issue all together with a code like that. Too lean is never a good sign. What I would suggest is buying a new front sensor, see if you stop getting codes. If not, then you have a bigger problem.
Update:
New O2 sensors installed.
Ordered the MSP harness from MSMS and the shop hacked it up to extend it to reach 2nd bung.
CEL gone for 300 miles now.
I can sometimes feel hesitation, I think the ECU is still adjusting to the new sensors.
Have a part number for the wiring harness from Mazda for the 2nd O2 sensor? My dad said that he thinks he threw out my stock manifold which still had my old sensor in it so I'll need to wire up the new one, preferably without cutting any stock wires.
