No.14 Poor Fuel Economy: Notes

NO.14 POOR FUEL ECONOMY [BP, BP WITH TC] DESCRIPTION & POSSIBLE CAUSE

14

Poor fuel economy

DESCRIPTION

Fuel economy is unsatisfactory.

POSSIBLE CAUSE

Contaminated air cleaner element
Engine cooling system malfunction
Improper transmission fluid level
Weak spark
Poor fuel quality
Erratic or no signal from CMP sensor
Improper coolant level
Inadequate fuel pressure
Spark plug malfunction
PCV valve malfunction
Brake dragging
Improper valve timing due to jumping out of timing belt
Contaminated MAF sensor
Improper engine compression
Exhaust system clogged
Variable valve timing system 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 injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION" and "AFTER SERVICE PRECAUTION".
    (See BEFORE SERVICE PRECAUTION )
    
    (See AFTER SERVICE PRECAUTION )
CAUTION:
- Disconnecting/connecting quick release connector without cleaning it may possibly cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.