P0307 on 2011-2013 Chevrolet Camaro: Cylinder 7 Misfire Causes and Fixes

What's Unique About the 2011-2013 Chevrolet CAMARO

On the 5th Generation Camaro with the 6.2L V8, the spark plug wires are a known weak point, as documented in official Technical Service Bulletins (TSBs). The rearmost cylinders, like number 7, are particularly susceptible to having their spark plug wires damaged by heat from the exhaust manifolds, especially if aftermarket headers have been installed. Owners on forums frequently report that a P0307 code appeared after header installation, which was traced back to a melted or arcing spark plug wire. Furthermore, the L99 engine found in automatic transmission models is equipped with Active Fuel Management (AFM), and the hydraulic lifters used for this system are a known failure point that can lead to a misfire on an AFM cylinder, which includes cylinder 7.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Flashing or solid Check Engine Light
• Rough idle or engine shaking
• Engine hesitation or stumbling during acceleration
• Noticeable loss of power
• Increased fuel consumption
• Smell of raw fuel from the exhaust
• Popping or ticking sound from the engine bay

Most Likely Causes

1. Damaged or Loose Spark Plug Wire 🔴 High Probability A manufacturer TSB specifically calls out loose spark plug wires as a cause for misfires on this platform. The wire for cylinder 7 is at the back of the engine on the driver's side, where it can be exposed to high heat from the exhaust manifold, causing it to degrade, melt, or arc. This is especially common after installing aftermarket headers.
   How to confirm: Visually inspect the spark plug wire for cylinder 7 (rearmost on the driver's side) for any signs of melting, cracking, or white ash indicating an arc. Ensure it is securely clicked onto both the spark plug and the ignition coil. At night, you can sometimes see the spark arcing from the wire to the engine block or header.
   Typical fix: Replace the spark plug wire. It is best practice to replace all 8 wires as a set.
   Est. part cost: $50-$120
2. Worn or Fouled Spark Plug 🔴 High Probability
   How to confirm: Remove the spark plug from cylinder 7. Inspect it for wear on the electrode, carbon fouling, oil deposits, or cracks in the porcelain. A good diagnostic step is to swap the cylinder 7 spark plug with the one from cylinder 5. If the code changes to P0305, the spark plug is the culprit.
   Typical fix: Replace the spark plug. It is highly recommended to replace all 8 spark plugs at the same time 🎬 See this step-by-step 5th Gen Camaro spark plug replacement guide to maintain consistent performance.
   Est. part cost: $40-$100
3. Failed Ignition Coil 🟡 Medium Probability
   How to confirm: Swap the ignition coil from cylinder 7 with the coil from an adjacent cylinder (e.g., cylinder 5). Clear the codes and run the engine. If the misfire code moves to P0305, the ignition coil is faulty.
   Typical fix: Replace the failed ignition coil.
   Est. part cost: $30-$75
4. Clogged or Faulty Fuel Injector ⚪ Low Probability
   How to confirm: Listen to the injector with a mechanic's stethoscope; it should make a consistent clicking sound. You can also check its resistance with a multimeter or perform a fuel injector balance test. Swapping the injector with another cylinder is also possible but is more labor-intensive.
   Typical fix: Clean or replace the fuel injector for cylinder 7.
   Est. part cost: $50-$150

Rare But Worth Checking

• Collapsed AFM Lifter (L99 Engine Only): On automatic transmission models, the L99 engine uses Active Fuel Management (AFM). The specialized lifters for this system, particularly on cylinders 1, 4, 6, and 7, are a known failure point. A collapsed lifter will fail to open the valves, causing a persistent misfire on that cylinder. Diagnosis involves removing the valve cover to observe rocker arm movement while the engine is running. A ticking noise is a common symptom.
• Low Cylinder Compression: This indicates a more serious internal engine problem, such as a worn piston ring, a bent or non-seating valve, or a damaged head gasket. A compression test is the first step to confirm, followed by a cylinder leak-down test to pinpoint the source of the leak.
• Broken Valve Spring: While less common than a lifter failure, a broken valve spring can cause a loss of compression and a severe misfire. This would be identified during a visual inspection when checking for a collapsed lifter.
• Intake Manifold Gasket Leak: A vacuum leak near the intake runner for cylinder 7 can lean out the air-fuel mixture and cause a misfire. This can be diagnosed with a smoke machine or by carefully spraying brake cleaner near the gasket and listening for a change in engine RPM.

Diagnosis Steps

1. Confirm the code P0307 is present 🎬 Watch: Two quick DIY methods to fix a P0307 code using an OBD-II scanner. Use the scanner's live data function (Mode $06) to monitor misfire counts for cylinder 7 in real-time.
2. Identify cylinder 7: It is the rearmost cylinder on the driver's side of the engine (The firing order is 1-8-7-2-6-5-4-3).
3. Visually inspect the spark plug wire for cylinder 7. Look for any signs of melting, burns, or looseness at either end. Pay close attention to its proximity to the exhaust manifold/header.
4. If the wire looks good, swap the ignition coil from cylinder 7 with the coil from cylinder 5 (the next one forward on the same bank). Clear the codes and drive the vehicle. If the code changes to P0305, the coil is bad.
5. If the code remains P0307, swap the spark plug from cylinder 7 with the one from cylinder 5. Clear codes and re-test. If the code becomes P0305, the spark plug is bad.
6. If the misfire still remains on cylinder 7, the issue is likely fuel-related or mechanical. Check the wiring connector to the fuel injector for corrosion or damage and listen for its operation with a stethoscope.
7. For L99 (automatic) engines: Listen carefully for a distinct ticking or clacking sound from the driver's side valve cover area, which could indicate a collapsed AFM lifter.
8. If a mechanical issue is suspected, perform a cylinder compression test on cylinder 7 and compare it to a healthy cylinder. A significant drop points to an internal problem.
9. If compression is low or a lifter issue is suspected, the next step is to remove the driver's side valve cover to visually inspect the valve springs and observe the rocker arm movement for cylinder 7 while the engine is cranked or briefly run.

Parts You'll Likely Need

• Spark Plugs (Set of 8) (OEM #ACDelco 41-162) — Spark plugs are a standard maintenance item and a primary cause of single-cylinder misfires.
  Trusted brands: ACDelco, NGK
  OEM price range: $60-$100
  Aftermarket price range: $40-$80
• Spark Plug Wires (Set of 8) (OEM #ACDelco 748TT) — This is a known failure point according to a TSB and owner reports, especially due to heat damage from the exhaust manifold.
  Trusted brands: ACDelco, NGK, MSD, Granatelli
  OEM price range: $70-$120
  Aftermarket price range: $50-$150
• Ignition Coil (OEM #ACDelco D510C) — A common failure point for ignition systems that can cause a misfire in a single cylinder.
  Trusted brands: ACDelco, Delphi, Bosch
  OEM price range: $50-$75
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent or affects other cylinders, a P0300 (Random/Multiple Cylinder Misfire) may be stored alongside P0307. This can sometimes point towards a vacuum leak or a failing AFM lifter that is beginning to affect multiple AFM cylinders.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Mentions that engine misfires (including P0307) can be caused by loose spark plug wires, requiring inspection and replacement.
• PIP5108 / PIP4568 (Related): While not specific to P0307, these bulletins discuss engine misfires, ticking noises, and low compression related to AFM lifter issues, which is highly relevant for L99-equipped Camaros.

Platform-Specific Known Issues

• A known issue documented by TSB #PIP4819A involves loose spark plug wires causing misfires across any of the 8 cylinders.
• Owners who have installed aftermarket headers are at a higher risk of experiencing a P0307 code due to the #7 spark plug wire melting or arcing against the header pipe due to tight clearances and high heat.
• The L99 V8 in automatic models features Active Fuel Management (AFM), which can lead to collapsed lifters. Cylinder 7 is one of the four AFM cylinders, making a collapsed lifter a significant potential cause for P0307 on these cars, often accompanied by a ticking noise.

Mechanic-Grade Diagnostic Values

• Port Fuel Injector Resistance — expected: 12 - 18 Ohms. Failure: A reading significantly outside this range, or an open/short circuit, indicates a failed injector coil.
• Ignition Coil Primary/Secondary Resistance — expected: Primary: ~0.8 Ohms, Secondary: ~7.1k Ohms. Note: These values are for the similar round-style D514A coil; the square D510C used on the Camaro should have comparable, but not identical, values.. Failure: A reading of infinity (open) or zero (short) on either winding indicates a failed coil.

Hidden / Shadow Codes Worth Checking

• Mode $06, OBDMID $A8: This is not a DTC, but a monitor ID within the scanner's Mode $06 data. OBDMID $A8 tracks misfire data specifically for Cylinder 7. Within this monitor, Test IDs (TID) $0B and $0C show the exponentially weighted moving average of misfires and the misfire count for the current/last drive cycle, respectively. (see via A professional scan tool or advanced OBD-II app that can display Mode $06 data. This allows a technician to see if cylinder 7 is registering misfires even if the count is not yet high enough to trigger the P0307 check engine light.)

Scan Tool Commands That Help

• GDS2 / Tech2 (or equivalent professional scanner): Cylinder Power Balance Test — This bidirectional test is used when a misfire is suspected but the cause is unclear. The tool commands the PCM to sequentially disable the fuel injector for each cylinder. A healthy cylinder will show a noticeable drop in engine RPM when disabled. If disabling cylinder 7 causes little or no change in RPM, it confirms that cylinder is not contributing power, narrowing the diagnosis to a spark, fuel, or mechanical issue on that specific cylinder.

Wiring & Ground Locations

• G106 (Driver Side) — Located on the rear of the driver's side cylinder head.. This is a critical engine-to-chassis ground. The ignition coils are grounded through the cylinder head to the block and ultimately to the chassis via this strap. A loose or corroded G106 can cause a weak or intermittent spark on the entire driver's side bank (cylinders 1, 3, 5, 7), leading to misfires.
• G103 — Located on the front of the passenger's side cylinder head.. While on the opposite bank, this is another primary engine ground. Any issue with the main engine grounding system can cause unpredictable electrical behavior, including erratic sensor readings and misfires.

Real Owner Repair Stories

• Camaro5 forum user (2012 Chevrolet Camaro (mileage: 28k)) — Check Engine Light with code P0307.
  ❌ Tried (didn't work) The user had the code appear 5 months after installing aftermarket headers.
  ✅ What actually fixed it The immediate and most common suggestion from other forum members was to re-check the spark plug wire for cylinder 7, ensuring it was fully seated on both the spark plug and the ignition coil, as they are often disturbed or not properly reconnected during header installation.
• Camaro5 forum user (2010 Camaro SS LS3) — Sudden rough running, shaking, and bad engine sounds while cruising on the highway, with a P0300 code.
  ❌ Tried (didn't work) Initial diagnosis only pointed to a random misfire.
  ✅ What actually fixed it The dealer found a broken outer valve spring on cylinder #8. The engine was saved from further damage because the stock dual-spring design meant the inner spring held the valve in place, preventing it from dropping into the cylinder. The fix was a relatively simple replacement of the broken spring without removing the cylinder head.
• Camaro5 forum user (2015 Camaro SS (L99 Automatic)) — Engine noise (ticking/knocking).
  ❌ Tried (didn't work) Owner was unsure of the cause.
  ✅ What actually fixed it Diagnosis confirmed a collapsed AFM lifter. This is a known weak point in L99 engines. The recommended permanent fix, discussed in the thread, is to perform an 'AFM/DOD delete,' which involves replacing the problematic AFM lifters with standard LS3/LS7 lifters and tuning the ECU to disable the Active Fuel Management system.

OEM Part Supersession History

• 12571595, 12619820 → 12639516, 12645725, 12680871 — These are part numbers for the AFM (Active Fuel Management) lifters used in the L99 engine. They have been updated over time due to high failure rates (collapsing).
  Heads up: The newer generation DFM (Dynamic Fuel Management) lifter, GM #12698946 (Elgin HL-7025), is backwards compatible and can be used in AFM applications. However, the original AFM lifters cannot be used in newer DFM engines. When replacing failed AFM lifters, it is common practice to replace all 8 AFM lifters, not just the failed one.
• ACDelco D510C (GM 12570616) → ACDelco D510C (GM 12611424) — Standard part number update and supplier changes over the vehicle's lifecycle.
  Heads up: The 2010-2015 V8 Camaros use a specific square-shaped ignition coil (D510C). Other GM vehicles use a visually similar but electrically different round-shaped coil (e.g., D514A). Using the wrong shape coil will result in it not mounting correctly and potential ignition issues. Always verify the coil shape before purchasing.

Model Year Variations Within This Range

• 2011-2013: For the V8 engines (LS3 and L99), there were no significant mechanical changes within this specific model year range that would alter the causes or diagnosis of a P0307 code. The primary variation remains the presence of the failure-prone AFM system on L99 (automatic) models versus its absence on LS3 (manual) models for the entire period.