2004 Land Rover Freelander

Engine Mechanical problem
2004 Land Rover Freelander 6 cyl Four Wheel Drive Automatic 140000 miles

when the machine is going up grade it looses it's power. No matter how far you puh the accelarator down it won't pick up. If you stop the machine and shut it off and start it again it will be fine until the next hill. The fastrest we can get out of it now is upto 50km/hr. Can you tell me what the problem could be?
February 25, 2010.

Hesitation, lack of acceleration, chugging, bogging etc.

Inspect and test all the following listed below: Oxygen sensors.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note: If it doesn't apply disregard

Feb 26, 2010.