Usually, your air/fuel mixture will become lean, and you can feel the same symptoms as from a lean mixture. Lean/Rich Mixtureīecause of the issues discussed, a faulty PCV valve can have the same symptoms as an intake leak, and the air/fuel mixture can end up being wrong. If you have any strange idle problems, it’s always a good idea to check the PCV valve first. High Idle RPM/Rough Idleīecause the PCV valve controls the airflow between the crankcase and the intake manifold, a broken PCV valve can have the same symptoms as an intake air leak, which can cause the idle RPM to get too high and other strange idle behaviors like a very rough idle. Some older cars with a PCV valve fitted without an electronically controlled engine will not have this symptom. To read the trouble code from the engine control unit, you have to use an OBD2 scanner.
When the engine light shows up, there is a trouble code stored in the engine control module. One of the most common and most noticeable bad PCV valve symptoms is probably the check engine light on your dashboard.
