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

What's Unique About the 2010-2013 Chevrolet AVALANCHE

The 2010-2013 Avalanche with the 5.3L V8 engine uses an Active Fuel Management (AFM) system to improve fuel economy by deactivating certain cylinders, including cylinder 7. This system's specialized lifters are a notorious weak point and a very common cause of misfires on this specific cylinder. While standard ignition issues are always possible, a persistent P0307 code, especially if accompanied by a ticking noise, often points directly to this well-documented AFM lifter failure, which is a more complex mechanical issue than a simple tune-up.

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 shaking idle.
• Engine hesitation or stumbling during acceleration.
• Flashing or solid Check Engine Light.
• Noticeable loss of engine power.
• Engine running rough.
• A distinct ticking or chirping noise from the engine.
• Service StabiliTrak warning message may appear on the dash.

Most Likely Causes

1. Failed Active Fuel Management (AFM) Lifter 🔴 High Probability → Shop Engine Valve Lifter Cylinder 7 is one of the four cylinders managed by the AFM system (cylinders 1, 4, 6, and 7). The lifters for these cylinders are a known high-failure part, prone to collapsing or sticking due to issues with oil pressure or internal wear. This is a widespread and well-documented problem on this generation of GM 5.3L V8 engines.
   How to confirm: Listen for a persistent ticking or chirping noise that increases with RPM. A definitive diagnostic involves removing the driver's side valve cover and starting the engine to visually confirm if the rocker arms for cylinder 7 🎬 Watch: How to diagnose a collapsed lifter on cylinder 7 are moving through their full range of motion. A collapsed lifter will result in little to no movement of one or both rocker arms. A compression test on cylinder 7 will also show very low or zero compression if a lifter has failed.
   Typical fix: This is a major repair. It involves removing the cylinder head 🎬 See this full repair guide for replacing a collapsed lifter to replace the failed lifter(s). Because a failed lifter can damage the camshaft, the camshaft should also be inspected for wear or damage to its lobes. Due to the high failure rate, many owners and shops recommend an 'AFM Delete,' which involves replacing all 16 lifters with standard (non-AFM) LS7-style lifters, replacing the VLOM (Valve Lifter Oil Manifold) with a standard valley cover, and reprogramming the ECU 🎬 Watch: What parts you need for a complete AFM delete to disable the AFM system. Some owners choose to also replace the camshaft with a non-AFM profile cam during this process.
   Est. part cost: $500-$1200 for AFM replacement parts or a full delete kit.
2. Worn or Fouled Spark Plug 🟡 Medium Probability → Shop Spark Plug These engines can suffer from excessive oil consumption due to issues with piston rings and the PCV system, which can foul spark plugs prematurely, particularly in AFM cylinders like #7. A Reddit user with a 2010 Avalanche noted their driver's side plugs were gunked up with oil. Spark plugs are also a standard maintenance item that wears out over time.
   How to confirm: Remove the spark plug from cylinder 7. Inspect it for wear, damage, carbon buildup, or oil/fuel fouling. A simple diagnostic step is to swap the cylinder 7 spark plug with one from another cylinder (e.g., cylinder 1). If the code changes to P0301, the spark plug is the culprit.
   Typical fix: Replace the spark plug. The recommended OEM Iridium plug is ACDelco 41-110. It is best practice to replace all 8 plugs if they are near their service life for balanced performance.
   Est. part cost: $10-$25 per spark plug.
3. Faulty Ignition Coil 🟡 Medium Probability → Shop Ignition Coil
   How to confirm: Swap the ignition coil from cylinder 7 with another cylinder (e.g., cylinder 1). Clear the codes and run the engine. If the misfire code moves to P0301, the ignition coil is faulty.
   Typical fix: Replace the failed ignition coil. The OEM part number is ACDelco D510C (12632479).
   Est. part cost: $40-$80.
4. Loose or Damaged Spark Plug Wire ⚪ Low Probability → Shop Spark Plug A specific Technical Service Bulletin (TSB #PIP4819A) was issued for 2010 models, explicitly stating that loose spark plug wires can cause misfire codes, including P0307.
   How to confirm: Visually inspect the spark plug wire for cylinder 7 for any signs of damage, burns, or corrosion. Ensure it is securely 'clicked' onto both the ignition coil and the spark plug.
   Typical fix: Replace the spark plug wire or the full set of wires. A quality set is recommended, such as ACDelco 9748RR.
   Est. part cost: $50-$100 for a set.
5. Clogged or Failed Fuel Injector ⚪ Low Probability → Shop Fuel Injector The fuel rail on these engines sits at a slight angle, with cylinder 7 being at the low end. Over time, debris or water from fuel can accumulate at the end of the rail and clog the #7 injector.
   How to confirm: After ruling out ignition issues, the fuel injector can be tested. This can be done by swapping the injector with another cylinder (a more involved job) or by using a fuel injector balance test to check its flow rate.
   Typical fix: Clean or replace the faulty fuel injector. A user on Chevrolet Forum fixed their P0307 by removing and cleaning the fuel rail and replacing the #7 injector and its O-rings.
   Est. part cost: $50-$150.

Rare But Worth Checking

• Worn Camshaft Lobe: → Shop Engine Camshaft A failed lifter can often cause damage to the corresponding camshaft lobe due to the roller seizing and grinding on the cam. If replacing a lifter, the camshaft should always be inspected for wear. TSB 19-NA-219 notes this as a potential cause for misfires that persist after initial diagnosis.
• Low Engine Compression: Internal engine issues like a leaking valve or worn piston rings can cause a loss of compression, leading to a misfire. A compression test on cylinder 7 will diagnose this.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0307. Note if the check engine light is flashing.
2. Listen for an engine ticking or chirping noise, which strongly suggests a valvetrain or lifter issue.
3. Inspect the spark plug wire for cylinder 7 to ensure it is secure and not damaged, as per TSB PIP4819A.
4. Swap the ignition coil from cylinder 7 with another cylinder (e.g., cylinder 1). Clear the codes. If the code changes to P0301, the coil is bad.
5. If the misfire remains on cylinder 7, swap the spark plug with another cylinder. If the code moves, the plug is bad.
6. If ignition components are good, the next most likely cause is a failed AFM lifter, especially if a ticking noise is present. Remove the driver's side valve cover and start the engine to observe rocker arm movement for cylinder 7.
7. If no lifter issue is apparent, check the fuel injector for cylinder 7. Consider that debris can collect at the end of the fuel rail, clogging the #7 injector.
8. If the misfire persists, perform an engine compression test on cylinder 7 to check for mechanical problems like bad valves or piston rings. A reading near zero points to a collapsed lifter.

Parts You'll Likely Need

• Active Fuel Management (AFM) Lifter Kit — This is the most common major failure causing a P0307 on this engine. Cylinder 7 is an AFM cylinder. Kits often include new lifters, guides, and gaskets.
  Trusted brands: ACDelco, Melling, Texas Speed & Performance
  OEM price range: $400-$600
  Aftermarket price range: $250-$450
• Ignition Coil (OEM #12632479) — A common failure point for any misfire code. It's responsible for providing the spark.
  Trusted brands: ACDelco, Delphi, Standard Motor Products
  OEM price range: $50-$80
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P0300 — If the AFM system is failing or there are widespread issues like a vacuum leak or low fuel pressure, multiple random misfires (P0300) can be logged along with the specific cylinder misfire.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Notes that loose spark plug wires can be a direct cause of misfire codes.
• 19-NA-219: Provides diagnostic guidance for engine noises and misfires, listing worn camshaft lobes and collapsed AFM lifters as primary causes to investigate when basic diagnostics fail.
• 10-06-01-008K: Addresses issues of excessive oil consumption which can lead to fouled spark plugs, a cause of misfires.

Platform-Specific Known Issues

• Active Fuel Management (AFM) Lifter Failure: This is the most notorious and significant issue. The 5.3L V8 engine's system for deactivating cylinders to save fuel puts extra stress on the specialized lifters for cylinders 1, 4, 6, and 7, leading to a very high rate of failure. A P0307 is often the first sign of a collapsed lifter in the rear driver's side cylinder.
• Oil Consumption and Fouled Plugs: A known issue related to the PCV system and piston rings (covered under TSBs like 10-06-01-008K) can cause excessive oil consumption, leading to oil-fouled spark plugs, particularly in AFM cylinders like #1 and #7.

Mechanic-Grade Diagnostic Values

• Fuel Pressure (Key-On-Engine-Off) — expected: 55-62 PSI. Failure: Pressure below 55 PSI or pressure that drops quickly indicates a weak fuel pump or a leak in the system.
• Fuel Injector Resistance — expected: 11.7 to 13.5 ohms. Failure: A reading significantly outside this range, or an open/short circuit, points to a failed injector coil.
• Ignition Coil Secondary Resistance — expected: 6,000 to 15,000 ohms (6k-15k Ω). Failure: A reading significantly outside this range indicates a failure in the secondary coil winding.
• AFM VLOM Solenoid Resistance — expected: 11 to 18 ohms. Failure: A reading outside this range when testing the pins on the Valve Lifter Oil Manifold (VLOM) connector suggests a faulty solenoid.

Scan Tool Commands That Help

• GDS2 / Tech2: Misfire Graphic / Misfire Counters — To view real-time and historical misfire counts for each individual cylinder. This helps confirm that the misfire is isolated to cylinder 7 and not random (P0300). A high number of current misfires on cylinder 7 confirms the fault location.
• GDS2 / Tech2: Cylinder Power Balance — This test deactivates one cylinder at a time and measures the drop in RPM. A cylinder that is already misfiring will show little to no RPM drop when deactivated, confirming it is not contributing power.
• GDS2 / Tech2: Crank/Cam Correlation Relearn — After replacing a crankshaft/camshaft sensor or reprogramming the PCM. An incorrect correlation can cause false misfire detection. Performing this relearn procedure can improve the accuracy of the misfire counter.

Wiring & Ground Locations

• G102 — Located at the left (driver's side) rear of the engine compartment.. This is a primary engine ground. A poor connection here can cause erratic behavior and weak spark from the ignition system, potentially leading to misfires.
• G103 — Located at the right (passenger's side) rear of the engine compartment, on the cylinder head.. This ground is critical for the Engine Control Module (ECM) and its sensors. Corrosion or a loose connection can cause a variety of engine management issues, including misfires.
• G104 — Located on the back of the left (driver's side) cylinder head.. This ground point is in close proximity to cylinder 7. A compromised connection here could directly impact the ignition coil or injector circuit for that cylinder.
• Cylinder 7 Injector Wiring — The fuel injector for cylinder 7 is located on the driver's side fuel rail, at the rearmost position.. The wiring harness to the injector can become brittle from heat cycles or damaged, leading to an intermittent connection and a misfire. The connector itself can also fail.

Real Owner Repair Stories

• LS1TECH Forum User (5.3L LC9 Engine (similar to Avalanche)) — P0307 misfire code.
  ❌ Tried (didn't work) Replaced all 8 AFM lifters after finding one collapsed on cylinder 7., Replaced the VLOM (Valve Lifter Oil Manifold) with a used one.
  ✅ What actually fixed it The user reported that even after replacing the collapsed lifter, the rockers for cylinder 7 still weren't moving when the engine was running, indicating the AFM system was still deactivating the cylinder. The final resolution was not posted in the thread, but the diagnosis confirmed the problem was electronic control of the AFM system, not just the mechanical lifter itself.

OEM Part Supersession History

• 12645725 → 12740071 — This is a common supersession for the AFM (Active Fuel Management) valve lifter. Part numbers are updated due to design revisions or manufacturer changes to improve reliability.
  Heads up: The newer part number 12740071 is the correct replacement for the older 12645725.