* Misfire(s): The most probable cause. A misfire occurs when one or more cylinders aren't igniting properly. This leads to the flashing light (indicating a potentially damaging condition) and rough running/vibration. Possible causes of misfires include:
* Spark plugs: Worn, fouled, or damaged spark plugs are a common cause.
* Ignition coils: These deliver the spark to the plugs. A failing coil will cause a misfire in the cylinder(s) it serves. Crown Vics often have issues with coil packs.
* Worn ignition wires: Though less common with modern vehicles, deteriorated wires can prevent proper spark delivery.
* Fuel injectors: A clogged or malfunctioning injector can prevent fuel from reaching the cylinder, causing a misfire.
* Valve problems: Worn, bent, or burnt valves can prevent proper combustion. This is less likely but possible, especially in a higher-mileage car.
* Engine compression: Low compression in one or more cylinders will result in a misfire. This often points to more serious internal engine problems.
* Catalytic Converter Issues: A severely clogged catalytic converter can cause back pressure that leads to misfires and rough running. The vibration might be less directly related than the misfires, however.
* Crankshaft Position Sensor (CKP) or Cam Position Sensor (CMP): These sensors tell the engine's computer the position of the crankshaft and camshaft. A faulty sensor can lead to erratic timing and misfires. This is less common but possible.
What to DO:
1. Don't drive the car extensively. Continuing to drive with a flashing check engine light and severe vibration risks causing significant damage.
2. Get the codes read: The flashing light is storing diagnostic trouble codes (DTCs) in the car's computer. A local auto parts store (like AutoZone, Advance Auto Parts, etc.) will usually read the codes for free. This will give you a much better idea of the specific problem.
3. Take it to a mechanic: Once you have the codes, take the car to a qualified mechanic. They can diagnose the problem accurately and make the necessary repairs. Ignoring this issue could lead to expensive engine damage.
In short, the flashing engine light and vibration strongly point to a serious ignition or fuel delivery problem. Getting the codes read is the first critical step, followed by professional diagnosis and repair.
