1994 Mercury Marquis Repair Question
Mercury Marquis Sensor Problem
FAILURE MODE EFFECTS MANAGEMENT
(FMEM) CODE 998
FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor's signals return to normal operating range, PCM will use those signals. A Code 998 will be displayed when FMEM mode is in effect.
Disonnecting the MAF etc could have triggerred this. Clear the code and retest and see what code comes up.
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