Lean Mixture

The following lists some of the possible combinations of exhaust gas values and the most likely causes.



A/F Ratio too Lean: possible problems, conditions or causes

Low Low High High
  • Lean fuel mixture,

  • Ignition misfire,

  • Vacuum leaks / air leaks (between air flow sensor and the throttle body),

  • Bad EGR valve or vacuum hoses misrouted,

  • Carburator settings incorrect,

  • Fuel injector/s bad,

  • O2 sensor bad or failing,

  • ECM malfunctioning,

  • Float level too low

Low High Low Low

Good combustion efficiency and catalytic converter working properly!


Automotive Equipment - in tune with the Future

Crypton Diagnostic Equipment - Automotive Diagnostic Workshop Equipment as used by Dealers and Garages

Crypton Diagnostic Equipment Home