OBD-II · P0302
P0302 Code: Cylinder 2 Misfire — Why It Happens and What It Costs
Cylinder 2 misfire detected
The short version
Same rule as every misfire code: a steady light allows short trips, a flashing light means stop now to protect the converter.
- Severity: Serious
- Most common cause: Ignition coil on cylinder 2
- 5 diagnosis steps in order
- 4 symptoms tied to this code
Darker bars are the more common causes; bar length is the top expected repair cost. Start with the dark, cheap causes before the expensive ones.
Can I keep driving?
Same rule as every misfire code: a steady light allows short trips, a flashing light means stop now to protect the converter.
Symptoms
- Idle vibration felt through the wheel and pedal
- Sluggish acceleration, especially uphill or loaded
- Higher fuel use and a strong exhaust smell
- Scan-tool misfire counters piling up on cylinder 2
Causes & repair cost
Ignition coil on cylinder 2
Most common$110 – $320
Worn plug or incorrect plug gap
Most common$25 – $90
Corroded coil connector or wiring
Possible$60 – $220
Weak-spraying fuel injector
Possible$150 – $500
Vacuum or PCV leak affecting the nearby cylinder
Rare$80 – $300
The typical bill is $40–$320 for a plug and coil. Add $60–$120 diagnostic labor if you cannot run the swap test yourself.
Estimate the repair for your carDiagnosis steps in order
- Record misfire counts before any change so you can measure the result
- Swap the coil with another cylinder and re-measure
- Inspect the connector for green corrosion or loose pins
- Measure fuel pressure and watch it under load
- Check for vacuum leaks and test the PCV valve
FAQ
Is P0302 worse than P0300?
It is not worse, it is clearer; naming the cylinder shortens diagnosis and saves shop labor.
Could a plug wire be the cause on older engines?
Yes — on engines with plug wires, a cracked wire or corroded boot is a frequent and cheap cause.
Why does the code return after a new plug?
Because the plug was a symptom, not the cause; oil, over-fueling, or low compression is still fouling it.
Should I clean or replace injectors?
Start with a professional pressurized clean; if the spray pattern is still uneven afterward, replacement is cheaper long term.
Related codes
All explained codes
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