1999 Mercury Cougar Repair Question
Check engine light - code: p1131
DTC P1131 indicates the system is correcting RICH for an overly LEAN condition. The Heated Oxygen Sensor (HO2S) voltage is less than 0.45 volts. This is usually due to a vacuum leak after the MAF. It can also be caused by a bad PCV valve or PCV system hose.
It can also be caused by low fuel pressure or a plugged injector.
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