1987 Mercury Marquis Repair Question
1987 Mercury Grand Marquise stalling problem and rough Idle
Here are some things to check. Load test the battery. Check that the battery cable connections are clean. Check for 12 volts to starter solenoid with the key in the start position. These things should be checked first then the ignition switch, starter and starter solenoid. One of these may be faulty. Also, check charging system. Here is the procedure we use to isolate a battery drain. Remove negative battery cable from the battery. Using a 12-volt test light, hook one end to the negative battery post the other end to the negative battery cable you just disconnected. The test light will glow or “light” if there is a drain. If the “light or glow” is faint, that is probably normal draw for the clock or computer. If the “light or glow” is bright, then there is a large drain. That should be corrected. Now start removing and replacing the fuses one by one until the light goes out; that one will be the circuit with the drain. Remember to hold in the button in the door jam for the interior lights.
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