What does it mean?
P1393 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 3 Misfire Detected Catalyst Damaging, Fuel Level Low .
Symptoms
- MIL flashing while the misfire is active
- Heavy shaking at idle and under acceleration
- Loss of power, jerking and hesitation when pulling away
- Fuel gauge showing a nearly empty tank when the code sets
- Exhaust smells of unburnt fuel, occasional popping from the tailpipe
- Engine may stumble or stall in tight corners
Likely causes
- Fuel level too low for the pump to feed reliably under lateral load or on gradients
- Worn, cracked or carbon fouled spark plug on cylinder 3
- Weak or failed ignition coil, or a plug boot arcing to the head
- Dirty, leaking or open circuit injector on cylinder 3
- Vacuum or intake gasket leak affecting that cylinder only
- Mechanical fault: low compression, a sticking valve or a worn cam lobe
- Restricted fuel filter or a tired fuel pump not maintaining pressure
How to fix it
- Add fuel and retest, a low tank alone can cause this pattern
- Confirm with live data that the misfire counter belongs to cylinder 3
- Swap the coil and plug with an adjacent cylinder to see if the fault migrates
- Examine the spark plug appearance for a clue: oil, coolant, fuel or heavy carbon
- Test the injector resistance, listen for its click and watch the fuel trims
- Check fuel pressure and volume under load and inspect the filter
- Perform a compression and leak down test on cylinder 3 if electrical and fuel checks pass
- Stop driving while the lamp flashes to protect the catalytic converter