I have a 94 mustang and it was throwing codes 311 and 314. My Smog/Air Pump was locked so I have been running with a smaller belt and eliminated it. I recently added a new smog pump and rerouted with a stock belt. I Ran codes again and I am getting a 314. Can anyone help me or point me to what I should be looking for?
Sounds like you need to check the system. For example, a couple of things that can happen are debris can clog the lines or the valves can get corroded or rusted. Here is some information:
311 - AIR system not working - Single, Right or Rear HO2S - Air Injection314 - AIR inoperative, Left or Front HO2S - Air Injection Air Pump System: By-Pass (Diverter Valve)Testing