1 Where applicable, remove the distributor cap and thoroughly clean it inside and out with a dry lint-free cloth. Examine the four HT lead segments inside the cap. If the segments appear badly burnt or pitted, renew the cap.

Make sure that the carbon brush in the centre of the cap is free to move and that it protrudes significantly from its holder.

2 Check the distributor cap for signs of tracking (indicated by thin black lines on the surface of the cap). Renew the cap if tracking is evident.

3 Wipe clean the HT leads and the coil tower.

4 Check the condition and security of all leads and wiring associated with the ignition system. Make sure that no chafing is occurring on any of the wires and that all connections are secure, clean and free from corrosion.