What does it mean?
P1344 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Random/Multiple Misfire Detected . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Flashing check engine light during the misfire, which warns of catalytic converter damage
- Engine shakes at idle and feels unsteady when stopped in traffic
- Hesitation, stumble and loss of power during acceleration
- Increased fuel consumption and a fuel smell from the exhaust
- Hard starting, especially when cold or after the vehicle has sat overnight
Likely causes
- Worn spark plugs with excessive gap, or plugs of the wrong heat range
- Vacuum leak from a cracked intake hose, a failed intake gasket or a stuck PCV valve leaning out several cylinders
- Low fuel pressure or volume from a weak pump, clogged filter or failing pressure regulator
- Dirty, restricted or leaking injectors affecting more than one cylinder
- Ignition coils breaking down under load, especially when several are the same age
- Exhaust gas recirculation valve stuck open, flooding the intake at idle
- Mechanical problems such as low compression, worn timing components or leaking valves
How to fix it
- Read the freeze frame and note load, rpm, coolant temperature and fuel trims when the misfire occurred
- Check misfire counters per cylinder in live data; if they are spread evenly, look at shared systems rather than one cylinder
- Look at fuel trim values, because strongly positive trims point to a vacuum leak or fuel delivery shortfall
- Inspect intake hoses, gaskets and the PCV system for leaks, using smoke testing where available
- Test fuel pressure and flow under load, and inspect the fuel filter where one is serviceable
- Inspect spark plugs for wear, fouling and oil, and evaluate the coils for breakdown under load
- If ignition and fuel check out, perform compression or cylinder leak-down testing to find a mechanical cause