1998 Mystique OBD Error Code woes
 

My beloved Mystique has been idling rough, stalling out and flat-out dying in the road (promptly restarts though). I have two codes to try and fix the issue:


p1131 Lack of Upstream Heated Oxygen Sendsor Switch - Sensor Indicates Lean - Bank No. 1

p0171 System too lean (Bank 1)

Google says it could be an O2 sensor or a vacuum leak.

I really have no clue how to resolve this and i cannot even begin to afford a mechanic.

Help?