P0301high severityPowertrain
Cylinder 1 Misfire Detected
on 2003 Mazda B2300 2.3L I4 · FWD
What this code means
The PCM has detected a misfire condition specifically in cylinder 1.
Symptoms
- Check Engine Light
- Rough idle
- Vibration
- Loss of power
- Fuel smell from exhaust
- Poor fuel economy
Common causes
- Worn or fouled spark plug #1
- Faulty ignition coil #1
- Damaged spark plug wire
- Faulty fuel injector #1
- Low compression cylinder 1
- Vacuum leak near cylinder 1
Diagnostic steps
- Swap ignition coil #1 with another cylinder to see if misfire follows
- Inspect spark plug #1
- Test fuel injector #1
- Check compression cylinder 1
- Check for vacuum leaks near cylinder 1
Repair notes
Try swapping coil first. If misfire follows the coil, replace it. If not, check plug, injector, then compression.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1