Dry, Fluffy Black Deposits - Cold or Carbon Fouling

Normal Operation And Carbon Fouling:

Symptoms: Dry, black deposits on the electrodes.

Possible Causes:

- On one or two plugs, may be caused by sticking valves or defective spark plug cables.

- On the entire set, may be caused by a clogged air cleaner.

- Poor Ignition Output

Note: Cold fouling is normal when the vehicle is only operated for short periods. The spark plugs do not reach a high enough operating temperature during short operating periods to burn fuel completely.