Fuel Economy Poor

1. Electronic Control Module (ECM) grounds.
2. Vacuum hoses.
3. Throttle body and intake manifold for air leaks.
4. Ignition wires.
5. Wiring harnesses and electrical connectors.
6. Improper tire inflation.
7. Air conditioning always on.
8. High idle speed.
9. High fuel pressure.
10. Exhaust Gas Recirculation (EGR) operation.
11. Injector stuck On.
12. Bad data from pressure sensor, Water Temperature Sensor (WTS), or Air Temperature Sensor (ATS).
13. Air cleaner.
14. Engine mechanical.