1983 Jaguar XJ6 mass airflow sensor

IDLE MIXTURE
NOTE:Mixture adjustment is not a part of normal tune-up procedure. It should not be performed unless fuel injection parts are replaced or vehicle fails emissions testing.

Connect special tools (BLT 1044 & 1047) to exhaust downpipe test points. With engine idling at 800 RPM, disconnect oxygen sensor and allow 1 minute for engine to stabilize.
Using an infrared analyzer, check CO reading. Reading should be 0.5-1.5%. If not, adjust by turning mixture adjusting screw on air flow meter housing.
Turn mixture screw clockwise to enrich mixture and counterclockwise to lean mixture. If correct setting cannot be attained, check that all electrical connections and all hoses are in good condition and properly located.
Replace oxygen sensor lead and disconnect test instruments.