And I say... Good day to you sir.

1. Rich air/fuel mixtures cause tip temperature to drop, causing fouling and poor driveability.

2. Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage.

3. It is important to read spark plugs many times during the tuning process to achieve the optimum air/ fuel mixture.