P0302: Cylinder 2 Misfire Detected
P0302 means the engine computer has detected that cylinder 2 is misfiring, so it is not burning its fuel properly. It is serious if the check engine light flashes, because unburnt fuel can damage the catalytic converter (the part of the exhaust that cleans emissions).
You can drive, but get it checked soon
With a steady light and mild symptoms, a short careful drive to a repair shop is usually acceptable. If the light flashes, stop driving as soon as it is safe, because the misfire is at a rate that can damage the catalytic converter. The engine may also lose power in limp mode.
What it means
The engine computer watches crankshaft speed. A cylinder that does not fire gives no push to the crankshaft, and the computer picks up that gap. P0302 is set when more than 90 % of the detected misfires come from cylinder 2. If the misfire rate is high enough to damage the catalytic converter, the check engine light flashes. At a lower rate that still affects emissions, the light comes on steadily after two trips (two separate drives). Ford and GM may shut off the injector of a misfiring cylinder to protect the catalyst, which can make the engine feel weaker. The usual causes are the ignition coil or spark plug of cylinder 2, its fuel injector, or low compression in that cylinder.
Likely causes
- Ignition coil of cylinder 2 faulty (coil, connector, ground)Very likely
The coil creates the spark for that cylinder, and if it or its connector or ground fails, the cylinder does not fire.
- Spark plug of cylinder 2 worn, sooted, cracked or wrongly gappedVery likely
A damaged or worn plug cannot light the fuel mixture reliably, and a plug cracked during installation can cause the same fault.
- Injector of cylinder 2 clogged or leaking, or its controlPossible
If the injector delivers too little or too much fuel, or is not triggered correctly, the mixture in that cylinder will not ignite properly.
- Low compression on cylinder 2 (valve, rings, head gasket) or local false airLess likely
If the cylinder cannot build enough pressure, or extra air leaks in near it, the mixture will not burn even with good spark and fuel.
- Water or oil in the plug wellLess likely
Liquid in the plug well can interfere with the spark or damage the plug and coil connection.
What you may notice
- Check engine light on, flashing when the misfire is at a catalyst-damaging rate
- Rough idle, jerking or vibration
- Loss of power or hesitation when accelerating
- Smell of unburnt fuel and higher fuel consumption
What to check, cheapest first
- 1Read the code and any freeze-frame data with a scanner, and check whether other misfire codes such as P0300 are also stored. · you can do it
- 2Inspect the coil connector and wiring of cylinder 2 for looseness, damage or corrosion, and check the plug well for water or oil. · you can do it
- 3Swap the cylinder 2 ignition coil with one from a neighboring cylinder, clear the code, and see whether the misfire moves to that cylinder. · you can do it
- 4Remove the spark plug of cylinder 2 and check it for wear, soot, cracks and correct gap; if the plugs are swapped for the test, see whether the misfire follows the plug. · you can do it
- 5Test the injector of cylinder 2 for correct electrical control and flow, and check for clogging or leaking. · mechanic
- 6Run a compression test on cylinder 2 and look for false air leaks if coil, plug and injector are fine. · mechanic
Related codes
Frequently asked questions
Can I drive with a P0302 code?+
Only with caution. If the check engine light is steady and the engine runs reasonably, a short trip to a shop is usually fine. If the light flashes, stop driving soon, because the catalytic converter can be damaged.
Can a loose gas cap cause P0302?+
It is not a typical cause. P0302 points to a misfire in cylinder 2, so the coil, spark plug and injector of that cylinder are the first things to check.
Will P0302 pass an emissions test?+
No. The code is emissions-relevant and turns the check engine light on, so the car will normally fail until the repair is done and the system has completed its drive cycle checks.
Can I fix P0302 myself?+
Often yes. Swapping a coil or spark plug is an easy job for many owners, and the repair is rated easy. Injector or compression problems need a mechanic.
Written with the help of AI from the public OBDex definition (CC0). Each make may use the code differently. Updated: 2026-11-10