OBD codes / P0302
P0302
SeriousCylinder 2 Misfire Detected
Treat P0302 with some urgency. A steady check-engine light with a mild misfire is usually drivable short-term, but a FLASHING light means raw fuel is reaching the catalytic converter and can ruin it — pull over and have it towed or diagnosed. Misfires also tend to worsen, so don't put the fix off.
What this code means
A misfire means a cylinder isn't burning its air-fuel mixture properly. P0302 points to one specific cylinder — number 2 — which makes it easier to diagnose than a random misfire. The usual cause is that cylinder's spark plug or ignition coil; a quick test is to swap the coil or plug with a neighboring cylinder and see if the misfire follows. Less commonly it's a clogged or dead fuel injector, or low compression in that cylinder from a valve or ring problem. Because unburned fuel can overheat the catalytic converter, a steady misfire shouldn't be left for long.
Symptoms you might notice
- Rough idle or shaking, often felt at a stop
- Loss of power or hesitation under acceleration
- Flashing check-engine light during an active misfire
- Reduced fuel economy
- Engine may stumble or be hard to start
What it costs to fix
Typical range: $80–$600 · about ~0.3–3 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Spark plug (single) | $4–$30 | ~0.3–1.5 hrs |
| Ignition coil (single) | $30–$150 | ~0.3–1 hrs |
| Fuel injector (single) | $100–$400 | ~1–3 hrs |
A single plug or coil is the cheap, common fix; an injector is pricier; low compression (a valve or ring issue) is a major repair that varies too much to quote — get it diagnosed if plug, coil, and injector all check out.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0302 for my exact vehicle →
How to fix P0302
Easy — basic tools, most owners can do this
- Find cylinder 2 for your engine layout
On an inline engine cylinder 2 is second from the front, but on V engines the numbering scheme is manufacturer-specific. Check a cylinder diagram for your exact engine before touching anything.
- Trade coil 2 with a known-good cylinder
Move the coil from cylinder 2 to another cylinder, clear the code, and take a short drive. If a new misfire code names the other cylinder, coil 2 is your fault; if P0302 comes straight back, the coil is innocent.
- Replace the cylinder 2 spark plug
Pull plug 2 while the coil is out and check the electrode and insulator. A fouled, cracked, or worn plug in one hole is the single most common cause of a one-cylinder misfire, and a new plug costs very little.
- Verify injector 2 is firing
A stethoscope on injector 2 should pick up a rhythmic click at idle; silence, or a click that sounds different from its neighbors, points at the injector. Swapping it with an adjacent one and watching whether the code moves confirms it.
- Test compression on cylinder 2 last
Good spark plus good fuel but a persistent P0302 usually means a compression problem. Compare cylinder 2's reading to the rest of the engine before assuming the worst — a low hole needs professional diagnosis.
DIY or shop? A home mechanic with a plug socket can handle the coil swap, plug replacement, and injector listening test in an afternoon on most engines. Save the shop visit for a failed compression test or for engines where cylinder 2 sits under the intake plenum and access turns a 20-minute job into a teardown.
Tools for the DIY steps: OBD-II scanner · Spark plug socket and extension · Ratchet · Mechanic's stethoscope or long screwdriver · Compression tester (optional)
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0302.
P0302 on specific vehicles
The likely causes shift by model. We’ve written up the patterns we see most:
Frequently asked
Can I drive with P0302?
With a steady (not flashing) light and only a mild misfire, short trips are usually fine — but get it looked at soon. If the light is flashing, the active misfire is dumping raw fuel into the catalytic converter and can destroy it; stop driving and have the car towed.
How do I know if it's the coil or the spark plug?
Swap cylinder 2's coil (or plug) with a neighboring cylinder and clear the code. If the misfire moves to the other cylinder, the part you moved is the culprit — a cheap way to avoid replacing the wrong thing.
How much does it cost to fix P0302?
Often modest — a single spark plug or coil is the common, inexpensive fix. It rises if the cause is a fuel injector, and a compression problem (valve or ring) is a major repair that varies widely. Confirm the cause before spending.
Should I replace all the coils or just cylinder 2?
If only cylinder 2 is misfiring, replacing just its coil/plug is reasonable. Some owners replace all of them at once if the parts are old and high-mileage, to avoid chasing the next one — but it isn't required to fix P0302.
Seeing P0302 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0302 for my vehicleSymptoms that trigger P0302
Drivers who get this code often notice one of these — each has its own likely-causes and cost guide:
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0302 from your phone — see our honest guide to the best OBD2 Bluetooth adapters.
Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.