1996 Mazda b2300

Engine Mechanical problem
1996 Mazda b2300 4 cyl Two Wheel Drive Manual 180000 miles

My truck been running great till now had a problem with the timing belt so I changed that when testin I noticed that, ther was a loss of power. Its not misfiring (engine runs fine in nuetral)and the timing is fine. Simptom it get more noticeble on a slit up hill have to keep itin first gear cant change to other gears, she wont go. Befor I could take her up very teep hill(on paved roads) in 4th gear
June 19, 2010.

If the transmission is not slipping-do below: Inspect and test all the following listed below: Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking, fuel filter 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.

Jun 20, 2010.