I realize there are hundreds of O2 sensor threads, so I apologize for this one. There seems to be so much conflicting information, so I'm just starting a new one.
Car - 1995 Ford Mustang, 3.8, stock everything (AFAIK)
Check Engline Light codes pulled by Advance Auto:
P0171 System Too Lean (Bank 1)
P0174 System Too Lean (Bank 2)
There are 4 O2 sensors (some threads said 2!) on the car. My question is concerning which ones need replaced. I've read that Bank 1 is the drivers side and then I've also read that Bank 1 is the passenger side. Which is it?
But... here is what Advance is telling me: Bank 1 is the front two and Bank 2 is the back 2. But people on here say Bank 1 is the Driver side (I assume front and back) and Bank 2 is the passenger side (front and back). Can somebody please clear this up for me?
Based on the two codes I posted above, which sensors should I be replacing (Both in the front, or 1 in front and 1 in back on the same side?) If there are two sensors per bank, how do you know which sensor for that bank needs replaced, based on the codes I posted above?