No. 14 Poor Fuel Economy: Notes

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Notes
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POSSIBLE CAUSES DESCRIPTIONS

14 POOR FUEL ECONOMY
DESCRIPTION  Fuel economy is unsatisfactory.
POSSIBLE CAUSE 
  • Contaminated air cleaner element
  • Engine cooling system malfunction
  • Weak spark
  • Spark plug malfunction
  • Poor fuel quality
  • Erratic signal from CKP sensor
  • Erratic or no signal from CMP sensor
  • Fuel pressure sensor or related circuit malfunction
  • ECT sensor or related circuit malfunction
  • Manifold absolute pressure (MAP) sensor or related circuit malfunction
  • Accelerator position sensor or related circuit malfunction
  • MAF sensor or related circuit malfunction
  • Contaminated MAF sensor
  • IAT sensor No.1 or related circuit malfunction
  • IAT sensor No.2 or related circuit malfunction
  • VSS or related circuit malfunction
  • Variable swirl system malfunction
  • Improper coolant level
  • Inadequate fuel pressure (high-pressure side)
  • Injection timing is incorrect
  • Fuel injector or related circuit malfunction
  • High pressure fuel pump malfunction
  • Fuel leakage
  • Fuel line restriction
  • Fuel filter clogging
  • PCV valve malfunction
  • Brake dragging
  • Clutch slippage
  • A/C system improper operation
  • Improper valve timing due to jumping out of timing chain
  • Improper engine compression
  • Turbocharger malfunction
  • Charge air cooler malfunction
  • Exhaust system and/or three-way catalytic converter clogging
  • EGR system malfunction
  • Vacuum leakage
  • Injector driver module or related circuit malfunction
    WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:
    • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.
    • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual.

      (See BEFORE REPAIR PROCEDURE ).

      (See AFTER REPAIR PROCEDURE ).

    RENDER: 1.0x

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    When to See a Mechanic

    Stop DIY work and contact a certified mechanic immediately if any of the following apply:

    • You smell fuel, burning insulation, or see smoke.
    • Brakes feel soft, pull hard to one side, or make grinding noises.
    • The engine overheats, stalls repeatedly, or misfires under load.
    • You are missing required tools, torque specs, or safe lifting equipment.
    • You are not confident in the next step or safety outcome.