P0307 on 2010-2013 Chevrolet Corvette: Cylinder 7 Misfire Causes and Fixes

What's Unique About the 2010-2013 Chevrolet CORVETTE

The high-performance V8 engines in the C6 Corvette generate significant heat, which can accelerate the wear of ignition components like spark plug wires. General Motors specifically issued Technical Service Bulletin #PIP4819A for these models, pointing directly to loose spark plug wires as a known cause for misfires. Additionally, for Z06 and 427 models equipped with the LS7 engine, a P0307 code that isn't resolved by simple ignition fixes can be an early symptom of the well-documented valve guide wear issue, a much more serious mechanical problem.

Diagnostic Flowchart

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

Symptoms You May Notice

• Rough or shaky idle
• Engine hesitation or stumbling during acceleration
• Noticeable loss of power
• Flashing Check Engine Light
• Fuel smell from the exhaust
• "Service Active Handling" message may appear on the Driver Information Center (DIC), often in conjunction with the misfire code.

Most Likely Causes

1. Loose or Failed Spark Plug Wire 🔴 High Probability GM Technical Service Bulletin #PIP4819A specifically calls out loose spark plug wires as a common cause for misfires on these engines. The connection can loosen from vibration and heat cycles. The #7 cylinder wire is in a tight, hot location at the rear of the engine bay, making it susceptible to damage or improper seating. One owner on Reddit found their P0307 was caused by a completely unplugged wire where the coil connection had rusted.
   How to confirm: Visually inspect the wire for cylinder #7 (driver's side, rear) for damage, burns, or arcing marks. Ensure it is firmly clicked onto both the ignition coil and the spark plug; you should feel a distinct 'pop' when it seats correctly. You can also check its resistance with a multimeter; high or infinite resistance indicates a bad wire.
   Typical fix: Replace the full set of spark plug wires. It's best practice to replace them all at once.
   Est. part cost: $60-$150
2. Worn or Fouled Spark Plug 🔴 High Probability
   How to confirm: Remove the spark plug from cylinder #7. Inspect it for wear, oil fouling, or damage to the electrode. To confirm, you can swap the #7 plug with another cylinder (e.g., #1), clear the codes, and see if the misfire code changes to P0301. If it does, the spark plug is the culprit. A user on CorvetteForum confirmed this exact diagnostic step worked for them.
   Typical fix: Replace the spark plug. It is highly recommended to replace all 8 spark plugs at the same time for consistent performance.
   Est. part cost: $8-$20 per plug
3. Failed Ignition Coil 🟡 Medium Probability
   How to confirm: Swap the ignition coil from cylinder #7 with another cylinder (e.g., #5). Clear the codes and run the engine. If the misfire moves to the new cylinder (e.g., P0305), the coil is faulty. This is a standard and effective diagnostic technique mentioned across many owner forums.
   Typical fix: Replace the failed ignition coil.
   Est. part cost: $40-$80
4. Clogged or Faulty Fuel Injector ⚪ Low Probability
   How to confirm: Listen to the injector with a mechanic's stethoscope; it should have a consistent clicking sound. Compare its sound to the injector on cylinder #5. You can also swap the injector with another cylinder to see if the misfire follows, though this is more labor-intensive and is usually performed after ignition system components are ruled out.
   Typical fix: Replace the faulty fuel injector.
   Est. part cost: $70-$150

Rare But Worth Checking

• Internal Engine Mechanical Failure (LS7 Valve Guide Wear): On LS7 engines (Z06, 427 Convertible), a persistent P0307 code that isn't resolved by ignition or fuel system parts can be a symptom of excessive valve guide wear. This was a known issue caused by a machining error at a GM supplier. If not addressed, it can lead to a valve dropping and catastrophic engine failure. Diagnosis requires a compression test and a leak-down test. A CorvetteForum user with P0307 and a 'Service Active Handling' message discovered their issue was a total lack of compression (~30psi) in cylinder 7, confirming a mechanical failure.
• Vacuum Leak: A leak in the intake manifold gasket near cylinder #7 can introduce unmetered air, causing a lean misfire. This is less common for a single-cylinder misfire but possible. Diagnosis is best done with a smoke machine to visually identify the leak.
• Collapsed Lifter: While less common, a collapsed or stuck Active Fuel Management (AFM) or standard lifter can cause a persistent misfire. This has been documented in platform mates like the Camaro SS with the LS3 engine. This is a significant mechanical repair requiring removal of the cylinder head.

Diagnosis Steps

1. Verify P0307 is the active code using an OBD-II scanner.
🎬 Watch: How to use an OBD2 scanner to troubleshoot rough idle.
2. Note if the Check Engine Light is solid or flashing. A flashing light indicates a severe, catalyst-damaging misfire.
3. Locate cylinder #7 (driver's side, rearmost cylinder).
4. Inspect the spark plug wire for a secure fit at both the coil and the plug. Check for any visible damage, burns, or corrosion. This is the most likely cause per TSB #PIP4819A.
5. If the wire looks good, swap the ignition coil from cylinder #7 with an adjacent one (like #5). Clear the codes and drive. If the code changes to P0305, the coil is bad.
6. If the code remains P0307, swap the spark plug from cylinder #7 with another cylinder (like #1). Clear codes and drive. If the code changes to P0301, the spark plug is bad.
7. If the ignition components are confirmed good, check the fuel injector. Listen for a steady clicking with a stethoscope. Compare its sound to the injector on cylinder #5.
8. If the cause is still not found, perform a compression test and leak-down test on cylinder #7 to rule out mechanical engine problems. For LS7 engines, this step is critical to check for the valve guide issue.

Parts You'll Likely Need

• Spark Plug Wire Set (OEM #ACDelco 9748UU (Standard)) — Directly cited by a GM TSB as the most common fix. Wires fail from heat and vibration. It's best to replace them as a set.
  Trusted brands: ACDelco, NGK, MSD
  OEM price range: $80-$120
  Aftermarket price range: $60-$100
• Iridium Spark Plug (OEM #ACDelco 41-110 (Original Spec) or 41-162 (Current Superseded Part)) — Spark plugs are a routine maintenance item and a primary cause of single-cylinder misfires. The 41-110 was the original plug, later superseded by the 41-162. Some owners on CorvetteForum report better idle quality after replacing newer 41-162 plugs with the original 41-110 spec, citing perceived differences in manufacturing quality.
  Trusted brands: ACDelco, NGK
  OEM price range: $12-$20 per plug
  Aftermarket price range: $8-$15 per plug
• Ignition Coil (OEM #ACDelco D510C (or 12611424)) — The individual coil for cylinder #7 can fail, preventing spark. It's a common failure point after plugs and wires.
  Trusted brands: ACDelco, Delphi
  OEM price range: $60-$80
  Aftermarket price range: $40-$60

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent or beginning to affect other cylinders, a P0300 (Random/Multiple Cylinder Misfire) may be stored alongside P0307. One owner reported their P0307 changed to a P0300 after swapping a suspected bad spark plug, indicating the problem was spreading.
• P0357 — This code indicates a fault in the ignition coil primary/secondary circuit for cylinder 7. It often appears with P0307 and points directly to a problem with the ignition coil or its wiring.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Malfunction Indicator Lamp on with engine misfires, directing technicians to inspect and replace loose spark plug wires.

Platform-Specific Known Issues

• TSB #PIP4819A: General Motors issued this bulletin specifically mentioning that P030x misfire codes on these engines are often caused by loose spark plug wires. The official fix is to inspect and replace any loose spark plug wires.
• LS7 Valve Guide Issue: On Z06 and 427 models with the 7.0L LS7 engine, a persistent misfire code can be an early warning of excessive valve guide wear. This was a known factory defect that could lead to a valve dropping into the cylinder, causing catastrophic engine failure. If basic ignition and fuel fixes do not resolve P0307 on an LS7, a professional evaluation of the cylinder heads (including a 'wiggle test' of the valves) is strongly recommended.

Mechanic-Grade Diagnostic Values

• OEM Spark Plug Wire Resistance — expected: 275-750 ohms. Failure: A reading above 750 ohms or infinite resistance (open circuit). Any single wire that is an outlier from the others.
• Ignition Coil Primary Resistance — expected: 0.4 - 0.6 ohms. Failure: A reading outside of this range indicates a faulty coil.
• Ignition Coil Secondary Resistance — expected: 5,000 - 7,200 ohms (5.0k - 7.2k ohms). Failure: A reading outside of this range indicates a faulty coil.
• Fuel Pressure at Fuel Rail (Key on, Engine off or at Idle) — expected: 58-62 PSI (approx. 400-427 kPa). Failure: Significantly lower pressure can cause a lean misfire. Pressure should remain steady.

Hidden / Shadow Codes Worth Checking

• Mode 6, Test ID $A2-$AB, Component ID $01-$08: These are not shadow codes, but onboard diagnostic test results for misfire counts for each cylinder. A high count for Component ID $07 (Cylinder 7) before a P0307 code is formally set can indicate an intermittent or developing misfire. This data can confirm which cylinder is the problem. (see via A professional scan tool capable of viewing Mode 6 data.)

Scan Tool Commands That Help

• GDS2 / Tech2 (or advanced aftermarket scanner): Cylinder Power Balance Test — This test should be used to confirm a misfire on cylinder 7 and compare its performance to other cylinders. The tool deactivates one cylinder at a time and measures the drop in RPM. A cylinder with a significantly smaller RPM drop than the others is not contributing its full power, confirming the misfire location without swapping parts.
• GDS2 / Tech2 (or advanced aftermarket scanner with bidirectional controls): Fuel Injector Balance / Disable Injector — After ruling out ignition components, a technician can use this function to disable the cylinder 7 fuel injector. If disabling the injector causes little to no change in engine idle or RPM drop compared to other cylinders, it points towards a problem in that cylinder (either the injector itself or a mechanical issue).

Wiring & Ground Locations

• G107 — Left side of the engine block, in the middle. On C5 diagrams, this grounds ignition coils 1-3-5-7.. This is a primary ground for the driver's side bank of ignition coils, including cylinder 7. A loose or corroded G107 can cause a weak or intermittent spark specifically on this bank, leading to a P0307 code.
• G106 — On the right rear side of the engine, above the starter solenoid.. This is a major engine ground point that provides a ground path for the Powertrain Control Module (PCM/ECM). A poor connection here can cause a wide range of erratic engine management behavior, including misfires.
• ECM Connector C2, Pin 7 — At the Engine Control Module (ECM), which is located behind the right front fender, accessible by removing the wheel well liner.. This specific pin is the control circuit for the cylinder 7 fuel injector (OG/BK wire). A technician would probe this pin to check for the control signal from the ECM, helping to diagnose a faulty injector driver in the ECM or a wiring issue between the ECM and the injector.

Real Owner Repair Stories

• CorvetteForum Member (C6 Corvette with LT4 hot cam kit, 1500 miles on motor) — Car started stuttering while accelerating hard at a drag strip.
  ❌ Tried (didn't work) Initial visual inspection at night missed the issue.
  ✅ What actually fixed it The pushrod for the second cylinder from the back on the driver's side (#7) was severely bent. The root cause was suspected to be incorrect valvetrain geometry (pushrod length) due to shaved heads and a different head gasket, or valve float from revving to 6400 RPM. The fix required replacing the bent pushrod and re-evaluating the valvetrain setup for proper geometry.

OEM Part Supersession History

• ACDelco 41-110 → ACDelco 41-162 — GM changed spark plug vendors from NGK (41-110) to Denso (41-162). The newer 41-162 plug has a slightly longer threaded portion, intended to place the electrode more centrally in the combustion chamber for efficiency.
  Heads up: While they are officially interchangeable, some owners report being unimpressed with the manufacturing quality of the newer 41-162 plugs. At least one owner on CorvetteForum found their engine ran smoother and resolved a misfire at idle by removing new 41-162 plugs and installing the original-spec 41-110 plugs, citing superior build quality on the older part.

Model Year Variations Within This Range

• 2010-2013: While the core LS3 engine remained consistent, minor changes occurred. For example, 2011 models received an updated Bluetooth system, and navigation units from 2011-2013 included a USB port in the center console, which are unrelated to this code. No significant changes to the ignition or fuel systems related to P0307 have been documented within this specific year range.