Which side (driver or passanger) is bank 2 on a 2006 S-Type 4.2 L? I have a P0174 reading and have checked over and over for vacuum leaks with carb cleaner but can't find any. The car is not running rough but has a check engine light. I reset the code and it does not come back on for 75-100 miles. The I/M on the OBDII says everything is ready except the O2's. After resetting.... there are no codes or pending faults...just the O2's not ready on the I/M. Therefore, I am assuming that if the P0174 comes back, the O2's would then be ready which would tell me that it is an O2 sensor problem. Does that sound logical? Also, which sensor should I be looking at changing front, rear or both? It should also be known that when the check engine light is on, the exhaust is so lean that you can smell it. Am I on the right track???Thanks for your help

 

Bank 2 is the LH side of the engine when viewed from the driver's position.

The best method for locating a possible vacuum leak is a smoke test performed under bright lights so small leaks can be located.

 

Don't assume, tends to lead bad places.

To confirm air leak check fuel trims.

 

swap the o2 to the other side. see if/when the code comes back it is bank 1 or still bank 2

 

Generic OBDII devices do not test both banks for readiness so I would first assume that there is an actual air leak and not a faulty read by the o2 sensor.