What P0302 actually means.
P0302 is the OBD-II code for "Cylinder 2 Misfire Detected." The PCM tracks crankshaft RPM millisecond-by-millisecond and measures the deceleration that should happen during each cylinder's power stroke. When cylinder 2's contribution is missing or weak, the code sets.
The diagnostic methodology is the same as P0301: identify whether it's ignition (coil/plug), fuel (injector), or compression on that specific cylinder. The swap test localizes the cause in 30 minutes. The difference with P0302 is mostly about where cylinder 2 sits on your engine — and on most V-engines, that means Bank 2, which often has worse access than Bank 1.
One other difference worth noting: P0302 is more commonly the first misfire to appear on V-engines, because Bank 2 cylinders often run slightly hotter than Bank 1 (heat management isn't always equal between banks), and heat is what kills coils, plugs, and gaskets. So if your V6/V8 throws its first misfire code, statistically P0302 is more likely than P0301.
Where is cylinder 2 on your engine?
Cylinder 2 location varies more than cylinder 1, because the firing order varies between engines. Common patterns:
Inline 4-cylinder engines: Cylinder 2 is the second cylinder from the timing belt/chain side. So if cylinder 1 is at the front (transverse), cylinder 2 is right behind it. Easy swap-test access — both cylinders are right next to each other.
Toyota V6 (1MZ-FE, 2GR-FE, 3.5L): Numbering is 1-3-5 on Bank 1 (front bank, near radiator) and 2-4-6 on Bank 2 (rear bank, against firewall). Cylinder 2 is the first cylinder of Bank 2 — typically the passenger end of the rear bank.
Honda V6 (J35): Numbering is 1-2-3 on Bank 1 (rear bank, oddly), and 4-5-6 on Bank 2 (front bank). So cylinder 2 is in the middle of Bank 1 — surprising but consistent across J35 engines.
Ford V8 (4.6L, 5.4L Triton): Numbering is 1-2-3-4 on the passenger side (Bank 1), and 5-6-7-8 on the driver's side (Bank 2). So cylinder 2 is the second cylinder on the passenger side. This makes the P0302 swap test relatively easy on Ford V8s.
GM V8 (LS, Vortec): Numbering is 1-3-5-7 on driver's side (Bank 1), 2-4-6-8 on passenger side (Bank 2). Cylinder 2 is at the front of Bank 2 (passenger side, front cylinder).
BMW / Mercedes V8s: Often reverse numbering — verify with service manual.
Common causes, ranked by probability.
From my shop log over 22 years. The cause distribution for P0302 is similar to P0301 but with a few cylinder-specific patterns I see often.
Diagnose it yourself in 30 minutes.
Same swap test methodology as P0301, but adapted for cylinder 2. The key difference: on V-engines, cylinder 2 is often on Bank 2 with worse access than cylinder 1.
Step 1 — Locate cylinder 2 (5 min)
Use your service manual or visible cylinder numbering. On inline-4: second cylinder from timing side. On Toyota V6: first cylinder of Bank 2 (rear bank). On Ford V8: second cylinder on passenger side. On GM V8: front of Bank 2 (passenger side, front).
If cylinder 2 is on Bank 2 of a transverse V6, expect harder access — you may need to remove an air intake duct or other components to reach the coil.
Step 2 — Swap the ignition coil (10-15 min)
With engine cold, remove cylinder 2's COP coil. Install it on cylinder 3 (or any other accessible cylinder). Take that cylinder's coil and install it on cylinder 2.
Important: pick a "donor" cylinder that's currently working. Don't swap with a cylinder you suspect is also marginal. The whole point is to see if the misfire follows the suspect coil to a known-good location.
Clear the code with your scanner. Drive normally for 5-10 miles, varying RPM and load.
Step 3 — Re-scan and interpret (3 min)
P0303 set (if you swapped with cyl 3): Coil is bad. Replace it. The bad coil is now sitting in cylinder 3's location.
P0302 returned: Coil is fine. Move to step 4.
Multiple cylinder codes: Something else is going on — check for paired lean/rich codes or compression issues.
No code set: Drive another 50 miles to confirm. Some misfires are intermittent.
Step 4 — Swap the spark plug (15-20 min)
If the coil swap didn't move the misfire, swap cylinder 2's plug with another cylinder. Same logic: if the misfire follows the plug to its new location, the plug is bad.
While you have the plug out, inspect it visually. Compare to a healthy plug from another cylinder. Black/sooty = running rich. White/chalky = running lean. Wet with oil = oil burning issue. Wet with gas = no spark (coil dead).
Step 5 — Check Bank 2 vacuum integrity (V6/V8 only) (10 min)
If cylinder 2 is on Bank 2 of a V-engine, check for a vacuum leak on that bank. With engine idling, propane test the Bank 2 intake manifold gasket. If idle smooths or RPM rises when propane crosses an area, that's your leak.
Also check the Bank 2 valve cover gasket and PCV connection — oil leaks here can wick into the cylinder 2 spark plug well, fouling the plug.
Step 6 — Test injector and compression (15 min)
If swap test, plug check, and vacuum inspection don't reveal the cause, test the cylinder 2 injector electrically (12-17Ω resistance for most modern injectors). Listen for click with a stethoscope at idle.
If the injector tests OK, do a compression test on cylinder 2. Pull the spark plug, install a compression gauge, crank for 5-7 cycles. Healthy: 150-200 PSI. If cylinder 2 is 50+ PSI lower than other cylinders, you have internal damage.
Bench-test specs for the diagnostic-curious.
The same electrical and mechanical specs from P0301 apply here. The unique element for P0302 is understanding cylinder 2's typical bank assignment across different engine families.
Required tools: a digital multimeter ($20), a compression gauge ($25), a stethoscope or screwdriver for injector listening, and a scan tool with code clearing.
Cylinder 2 location across common engines
This is the most useful table for P0302. Find your engine family and you'll know where cylinder 2 sits.
Cylinder 2 location lookup table
| Engine Family | Cylinder 2 Bank | Physical Location | Access Difficulty |
|---|---|---|---|
| Inline 4-cyl (most cars) | Same bank as cyl 1 | Second from timing side | Easy |
| Inline 6-cyl (BMW, older Toyota) | Same bank as cyl 1 | Second from timing side | Easy |
| Toyota V6 (1MZ, 2GR, 3.5L) | Bank 2 (rear) | Front of Bank 2 (passenger end) | Hard (firewall side) |
| Honda V6 (J35) | Bank 1 (front) | Middle of Bank 1 | Medium |
| Ford V8 (4.6, 5.4, 5.0) | Bank 1 (passenger) | Second from front, passenger side | Easy |
| GM V8 (LS, Vortec) | Bank 2 (passenger) | Front of Bank 2 | Easy |
| Chrysler V8 (HEMI, Pentastar) | Bank 2 (driver) | Front of Bank 2 | Medium |
| BMW V8 (N62, S65) | Bank 1 (driver) | Second from front, driver side | Medium |
Ignition coil resistance specs (cylinder 2)
Same as P0301 — coil resistance specs are universal across cylinders. Test with engine off, coil unplugged.
| Coil Type | Primary Resistance | Secondary Resistance | Common Brands Using |
|---|---|---|---|
| Standard COP | 0.4–1.5 Ω | 5–15 kΩ | Toyota, Honda, GM, Ford |
| Pencil COP | 0.5–1.0 Ω | N/A integrated | BMW, VW, Audi |
| Coil pack (older) | 0.5–2.0 Ω | 8–18 kΩ | Some early 2000s vehicles |
| Heat-cycled test | Should not double cold→hot | Watch for heat-induced opens | Bank 2 often heat-affected |
Compression test specifications
Same target as any other cylinder — what matters is comparing cylinder 2 to its neighbors. Pull the plug, install gauge, crank 5-7 cycles with throttle wide open.
| Cylinder 2 Reading | vs Other Cylinders | Diagnosis | Action |
|---|---|---|---|
| 150-200 PSI | Within 10% | Healthy | Look elsewhere — coil/plug/injector |
| 130-150 PSI | 10-20% lower | Worn rings or aging valves | Wet test to confirm rings vs valves |
| <100 PSI | 50+ PSI lower | Major mechanical damage | Burnt valve or blown HG — head work needed |
| 0 PSI | No compression | Catastrophic failure | Hole in piston, dropped valve, broken rod |
Torque specifications
| Component | Torque (lb-ft) | Torque (Nm) | Notes |
|---|---|---|---|
| Spark plug (M14, gasketed) | 18–22 lb-ft | 25–30 Nm | Light anti-seize on threads |
| Coil-on-plug bolt | 7–10 lb-ft | 10–14 Nm | Plastic threads — easy to strip |
| Bank 2 intake manifold (V6/V8) | 7–9 lb-ft | 10–12 Nm | Star pattern, multiple passes, new gasket |
| Bank 2 valve cover bolts | 6–9 lb-ft | 8–12 Nm | Don't crush rubber gasket |
Diagnostic procedure summary
- Verify cylinder 2 location — Service manual lookup for your specific engine.
- Swap test the coil — Move cyl 2 coil to cyl 3. If misfire follows, replace.
- Swap test the spark plug — Same logic, use cyl 4 as donor.
- Check Bank 2 intake gasket (V6/V8) — Propane test if cyl 2 is on Bank 2.
- Test injector resistance + click — Multimeter and stethoscope.
- Compression test cyl 2 vs neighbors — Definitive mechanical diagnosis.
What P0302 feels like.
| Symptom | How common |
|---|---|
| Rough idle (different feel from P0301) | 85% |
| Loss of power, especially under load | 70% |
| Hesitation on acceleration | 55% |
| Vibration through steering wheel (V6/V8) | 45% |
| Reduced fuel economy | 45% |
| Flashing CEL (severe) | 15% |
The vibration through the steering wheel is more common with V6/V8 P0302 than with inline-4 P0302 — because Bank 2 misfires create an asymmetric balance issue that's transmitted through engine mounts. Inline-4 misfires are felt more in the seat than the wheel.
Real cost breakdown.
Costs are similar to P0301 with one exception: V6/V8 Bank 2 access drives up shop labor:
| Repair | Parts | Labor | DIY Cost | Shop Cost |
|---|---|---|---|---|
| Inline-4 cyl 2 coil | $30–$100 | 15 min | $30–$100 | $150–$250 |
| V6/V8 Bank 2 cyl 2 coil | $30–$100 | 30–60 min | $30–$100 | $200–$400 |
| Single spark plug (any layout) | $5–$20 | 10–30 min | $5–$20 | $60–$200 |
| Single fuel injector | $80–$200 | 1–3 hrs | $80–$200 | $300–$700 |
| Bank 2 intake gasket | $30–$80 | 3–6 hrs | $30–$80 | $400–$900 |
| Walnut blasting (GDI carbon) | $40 (media) | 3–5 hrs | $300–$500 (kit + media) | $400–$700 |
| Compression issue | $200–$600 | 10–20 hrs | $300–$800 | $1,500–$4,000 |
The right order to actually fix it.
- Confirm cyl 2 location ($0) — Service manual or AllData. Don't guess.
- Swap test the coil ($0) — Move to cyl 3 (or any healthy donor). Drive 5-10 miles. Solves about 42% of cases.
- Swap test the plug ($0) — If coil swap didn't move it. Solves another 22%.
- Replace failed component ($5-100) — Once swap test identifies the bad part.
- Check Bank 2 vacuum (V6/V8) ($0-20) — Propane test the intake gasket. Replace if leaking.
- Run injector cleaner ($8) — Bottle of Techron through tank if injector suspected.
- Test injector electrically ($0) — Resistance + click test.
- Replace injector if bad ($80-200) — Match OEM or quality aftermarket.
- Compression test ($25) — Last diagnostic step before head work.
- Internal engine work ($1,500+) — Last resort. Only if compression is significantly low.
Can you keep driving?
Same rule as P0301: solid CEL = OK short-term, flashing CEL = stop.
- Solid CEL with P0302: 1-2 weeks of normal driving is acceptable while you sort out the fix. Avoid heavy throttle and high-RPM driving.
- Flashing CEL with P0302: Active misfires reaching the catalytic converter in real time. The unburned fuel ignites in the cat and can melt it within a few miles. Do not drive — fix or tow.
- V-engine specific risk: Sustained P0302 on a V-engine can damage the Bank 2 catalytic converter specifically. New Bank 2 cat is $400-1,500. Fix the misfire before the cat fails too.
P0302 patterns by brand.
| Brand | Most common cause | Notes |
|---|---|---|
| Toyota V6 (Camry, Sienna) | Bank 2 coil failure | Cyl 2 is Bank 2 (rear bank) — heat exposure makes coils fail first here |
| Honda V6 (Pilot, Odyssey) | Spark plug carbon-fouled | J35 cyl 2 is on Bank 1 actually — easier access than Toyota |
| Ford V8 (5.4L Triton) | Coil failure | Cyl 2 is Bank 1 (passenger) — easy access. Coils famous for short life |
| GM 5.3L Vortec | Coil failure | Cyl 2 is Bank 2 (passenger front) — replace as set if multiple coils aged |
| Inline-4 (Civic, Corolla) | Coil or plug | Standard inline-4 — cyl 2 is right next to cyl 1, easy access |
| VW/Audi 2.0T | Carbon-fouled valve (GDI) | Walnut blasting common at 80-100k miles to clear intake valve carbon |
| BMW N54/N55 (inline-6) | Pencil coil failure | Replace as set when one fails — others typically follow within months |
| Subaru boxer engines | Spark plug or coil | Boxer layout makes plug access difficult — budget extra time |
Questions people always ask about P0302.
Same severity — both are single-cylinder misfires with identical implications. The practical difference is access: on V-engines where cyl 2 is on Bank 2 (Toyota, GM), the work takes longer and costs more. Inline-4 P0302 is similar to P0301 — easy.
Very likely yes. P0174 is Bank 2 lean. If cylinder 2 is on Bank 2 (most V6s), a Bank 2 intake gasket leak can cause both — lean condition triggers P0174, and the lean cylinder misfires triggering P0302. Fix the vacuum leak and both codes should clear.
If your V-engine has 100k+ miles AND Bank 2 access is hard (Toyota Camry V6), this might actually be cost-effective — you're already in there. But for newer engines or accessible designs, do the swap test first. Replace just the bad coil, monitor for 6 months, replace others only if they fail too.
No — gas cap issues cause P0455 (large EVAP leak), not misfires. EVAP leaks affect fuel vapor capture, not cylinder ignition. If you have both a gas cap issue AND P0302, they're unrelated. Fix them separately.
Intermittent idle-only misfires often point to a vacuum leak (idle is when vacuum is highest, magnifying small leaks) or a worn spark plug barely making contact. At higher RPMs the engine has more momentum to "carry" through a weak combustion event. Try the swap test at idle specifically.
Sometimes, if the cause is a partially clogged injector. A bottle of Techron or BG 44K through the fuel tank can dissolve mild deposits and restore proper spray pattern. Worth trying ($8) before replacing the injector ($80-200). Won't help with electrical injector failures or with non-injector misfire causes.