2000 Jaguar S-Type P0171 and P0174 codes

The MAF sensor is on the engine air intake duct

P0171/P0174

A lean fuel condition can be caused by:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

Thanks a lot! Happy San Valentine day!

Look for vacumm leaks. The vacumm elbows crack and leak on these cars. The one elbow you can see on the back of the engine. The other one is under the lower intake assembly. Take it to a should, just don't put a MAF sensor in it.