📟
Get a scan tool before spending a dollar. For P0302, a bidirectional Bluetooth OBD2 scanner lets you do a cylinder contribution test - cuts the engine on cylinder 2 and measures the RPM drop. Zero drop = confirmed dead cylinder. See top-rated scanners on Amazon ↗
💡 Pro tip: P0302 is a "single cylinder" code - this is actually good news because you know exactly where to look. The coil-swap test (move cylinder 2's coil to another cylinder) takes 10 minutes and confirms or rules out the coil without buying anything.
🗺️ Where Is the Problem?
P0302 - fault isolated to cylinder #2 only; all other cylinders firing normally
These are statistical causes across ALL vehicles - your exact car may rank differently
For example, on a Honda 4-cyl the downstream O2 sensor causes P0302 64% of the time, but on a GM 5.3L V8 the catalytic converter is the cause 71% of the time. Get a probability ranking built specifically for your year, make, model, and mileage.
🔎 Get the ranking for my exact car - $5.99 →
🎯 Top Causes & Probability
48%
#1 - Most Likely
Failed Ignition Coil (Coil-on-Plug, Cylinder 2)
Modern engines use individual coil-on-plug units. When the cylinder 2 coil fails, it stops generating spark - complete combustion failure. The coil-swap test is definitive: move cylinder 2's coil to cylinder 3. If the code changes to P0303, you've confirmed the coil. Replace it.
OEM Coil
$40–$150
Aftermarket
$25–$60
⚡ DIY Difficulty
Easy
30%
#2 - Check First
Worn or Fouled Spark Plug (Cylinder 2)
A plug worn past spec, oil-fouled, or cracked insulator causes weak or absent spark. Inspect the plug closely - carbon fouling suggests rich running or oil consumption on that cylinder, which changes the repair plan. Plugs should be replaced every 60k–100k miles depending on type.
Single plug
$8–$30
Full set
$30–$120
⚡ DIY Difficulty
Easy
15%
#3 - Less Common
Leaking or Dead Fuel Injector (Cylinder 2)
A leaking injector floods cylinder 2 (rich/wet fouled plug) while a dead injector starves it (lean). You can verify by performing a cylinder contribution test on a bidirectional scanner - cylinder 2 will show zero power contribution. Injector cleaning may fix a partially clogged one; dead injectors must be replaced.
Clean/rebuild
$20–$60
Replace
$100–$300
⚡ DIY Difficulty
Medium
🚗 Most Affected Vehicles
| Vehicle | Cylinder 2 Location | Common Root Cause | Typical Mileage |
|---|---|---|---|
| Ford F-150 4.6L / 5.4L | Passenger side, front | Coil boot failure | 80k–120k mi |
| Dodge Ram 5.7L HEMI | Passenger side bank | MDS solenoid, lifter | 60k–100k mi |
| Honda Accord 2.4L K24 | Second from front | Spark plug interval | 90k–130k mi |
| Chevy Silverado 4.8/5.3L | Passenger side front | AFM lifter or coil | 60k–90k mi |
| Jeep Grand Cherokee 3.6L | Front of engine | Cam follower wear | 60k–80k mi |
🔧 Step-by-Step Diagnosis
- Coil Swap Test - This takes 10 minutes. Move the coil from cylinder 2 to cylinder 4. Clear codes, drive briefly. If P0302 becomes P0304, the coil is bad. If P0302 stays on cylinder 2, the coil is good.
- Inspect and Replace Spark Plug - Pull the cylinder 2 plug. Check gap (use a feeler gauge), look for cracks, note any fouling color. Black/oily = oil consumption issue. White/tan = normal. Grayish = lean condition.
📍 Find a Trusted Shop Near You
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Tips for Choosing a Shop
- Ask if they charge a diagnostic fee and whether it applies toward the repair
- Request a written estimate before approving any work
- Ask specifically about the part brand - OEM vs. aftermarket matters for this code
- Check Google reviews for recent mentions of the specific repair you need
Community Reports
CR
RESOLVED
P0302 on my EcoBoost. Did the coil swap - P0302 followed the coil to cylinder 4 (became P0304). Ordered a genuine Motorcraft coil for $38. 20 minute job. While I was in there replaced all 6 plugs since they were at 70k. Total $140 and no more codes. Rough idle completely gone.
MP
RESOLVED
P0302 on the HEMI. Tried coil and plug - still misfiring. Turned out to be the MDS (Multi-Displacement System) solenoid on cylinder 2 stuck in deactivation mode. It was "turning off" the cylinder during normal operation. Solenoid was $85. This is a common HEMI issue - always check MDS solenoids if plugs and coils don't fix it.
SJ
RESOLVED
P0302 showed up as an intermittent rough idle issue. Swapped coil - code didn't follow. Replaced plug (original at 143k!). Code cleared, ran great for 2 weeks, then came back. Compression test showed 130 PSI on cylinder 2, 175 on others. Head gasket was leaking into that cylinder. $1,800 repair but at least I know what it was.