RANGE ROVER Engine Size : 4.6
Question: I HAVE CODES PO171 ,PO174 AND ROVER HAS NO POWER MOVING OF, IT STUTTERS & SPITS WITH NO POWER TAKING OFF, ALSO WOULD LIKE TO KNOW WHERE TO FIND THE PCV VALVE.

Answer: P0171 and P0174 are codes for a lean condition. This is usually caused by a vacuum leak. Sometimes it is caused by a faulty oxygen sensor, but usually a vacuum leak. Possible that the intake manifold gaskets are leaking, or the throttle gasket. With the lack of power, this may also be a low fuel pressure problem caused by a plugged fuel filter or failing fuel pump. The PCV location depends on the year of your vehicle. Most are internal to the inside of a valve cover on the 4.6L. also know as the spiral separator.