2011-2014 Ford F-150 3.5L EcoBoost: OBD Codes and What to Check First

Codes recorded for this model

• P0300 Random or Multiple Cylinder Misfire Detected Stop driving Shop $120–$900 2 weeks estimate
• P0301 Cylinder 1 Misfire Detected Stop driving Shop $120–$700 2 weeks estimate

What to check first on this engine

These come from how this specific engine fails, not from a generic code list.

1. 1

   Expect carbon, not a bad coil

   Direct injection on the 3.5L EcoBoost lets carbon build on the intake valves. That produces misfire codes that look like ignition faults but survive a coil swap.

2. 2

   Move a coil and reread the counters

   Swapping a coil to a neighboring cylinder and driving 20 miles separates an ignition fault from a carbon or compression problem for the cost of a drive.

3. 3

   Check misfire counters at idle and under load

   A misfire that only appears under boost points at a different cause than one that shakes the car at idle. Note which one you have before spending anything.