Intermittent Problem Diagnosis

WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to PCM setting a DTC which may help in diagnosis. To reproduce conditions creating an intermittent fault, use the following methods:

Lightly vibrate component.
Heat component.
Wiggle or bend wiring harness.
Spray component with water.
Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic DTCs. See QUICK TEST in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. Use test results to identify a faulty component or circuit.