Hombre S Regular Cab 4WD V6-4.3L (1999)
A broken or cracked lower insulator tip (around the center electrode) may result from damage during re-gapping or from "heat shock" (spark plug
suddenly operating too hot).
Damage during re-gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to crack.
When re-gapping a spark plug, make the adjustment by bending only the ground side terminal, keeping the tool clear of other parts.
"Heat shock" breakage in the lower insulator tip generally occurs during several engine operating conditions (high speeds or heavy loading) and may be
caused by over-advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator material to crack.
Spark plugs with less than the recommended amount of service can sometimes be cleaned and re-gapped ,then returned to service. However, if there is
any doubt about the serviceability of a spark plug, replace it. Spark plugs with cracked or broken insulators should always be replaced.
