Poor Fuel Mileage

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2000 Isuzu VehiCROSS, 2000 Isuzu Trooper, 2000 Isuzu Rodeo, 2000 Isuzu Hombre, and 2000 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.

Check fuel pressure.
Check vacuum hoses.
Check ignition timing.
Check spark plugs.
Check for correct tire pressure, vehicle carrying heavy loads or poor driving habits.
Check if A/C is on all the time.
Check for restricted air filter.
Check for restricted exhaust system.
Check for proper speedometer calibration.
Check EGR system.
Check oxygen sensor for silicone or lead contamination.
Check engine compression.
Check for dragging brakes.
Check gasoline quality.
Check for cooling system running too hot or cold.
Check for faulty thermostat.
Check for faulty Torque Converter Clutch.
Check for leaks is air intake system and crankcase.