A condition caused by an air/fuel mixture that is too lean to sustain combustion. Lean misfire causes one or more cylinders to pass unburned fuel into the exhaust system causing a big increase in hydrocarbon (HC) emissions. Symptoms include a rough idle and hesitation or stumble on acceleration. Lean misfire is often caused by vacuum leaks or an EGR valve that's stuck open.
© 2000 - 2002 Vincent T. Ciulla
