Diagnostic Aids

Ensure engine is not overheating and has not been subjected to conditions which would create an overheating condition (i.e., overload, trailer towing, hilly terrain, heavy stop-and-go traffic, etc.). A "shifted" (mis-scaled) sensor could result in poor driveability complaints. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE table at various temperature levels to evaluate possibility of a "shifted" (mis-scaled) sensor.

An intermittent condition may be caused by poor connection, rubbed-through insulation, or a broken wire inside insulation. Check PCM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, or poor terminal-to-wire connections before component replacement.