P0307 on 2010-2013 Cadillac Escalade EXT: Cylinder 7 Misfire Causes and Fixes

What's Unique About the 2010-2013 Cadillac ESCALADE EXT

The 6.2L V8 (L94) engine in this generation of Escalade EXT is equipped with Active Fuel Management (AFM), a system designed to improve fuel economy by deactivating certain cylinders under light loads. Cylinders 1, 4, 6, and 7 are the AFM cylinders. The hydraulic lifters associated with this system are a known weak point and are prone to failure, often leading to a collapsed or stuck lifter that causes a persistent misfire specifically in an AFM cylinder like number 7. This makes a P0307 code on this vehicle potentially more serious than a simple ignition component failure, often requiring extensive top-end engine repair.

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
• Hesitation or stumbling during acceleration
• Noticeable loss of power
• Engine ticking, chirping, or squeaking noise, especially on cold starts, that may point to a lifter issue.
• "Service StabiliTrak" or "Service Traction Control" message may appear on the dash, as the engine power imbalance can confuse the stability control system.

Most Likely Causes

1. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil The factory ignition coils are known to degrade from high under-hood temperatures, leading to internal voltage leaks and weak spark after 80,000-100,000 miles.
   How to confirm: Swap the ignition coil from cylinder 7 with another cylinder (e.g., cylinder 1 or 5). Clear the codes and drive the vehicle. If the code changes to P0301 or P0305, the ignition coil is the faulty part.
   Typical fix: Replace the faulty ignition coil. It is often recommended to replace the corresponding spark plug at the same time.
   Est. part cost: $40-$80
2. Worn or Fouled Spark Plug 🔴 High Probability → Shop Spark Plug Oil consumption issues related to the AFM system can sometimes lead to fouled spark plugs on affected cylinders.
   How to confirm: Remove the spark plug from cylinder 7 and inspect it. Look for a cracked insulator, heavy carbon buildup, oil fouling, or a worn electrode. A plug that looks brand new after many miles could indicate a fuel delivery issue, while a wet, fuel-fouled plug could indicate an ignition or injector problem.
   Typical fix: Replace the spark plug for cylinder 7. It is best practice to replace all 8 spark plugs at the same time for even performance. The recommended spark plug is an ACDelco Iridium plug.
   Est. part cost: $8-$20 per plug
3. Bad Spark Plug Wire 🟡 Medium Probability → Shop Spark Plug A manufacturer TSB (#PIP4819A) specifically mentions inspecting and replacing loose spark plug wires for misfire codes on 2010 models.
   How to confirm: Visually inspect the wire for cylinder 7 for any signs of damage, burns, or corrosion on the contacts. Ensure it is securely connected at both the ignition coil and the spark plug. You can also test its resistance with a multimeter.
   Typical fix: Replace the spark plug wire. It is recommended to replace the entire set of 8 wires.
   Est. part cost: $50-$100 for a set
4. Failed AFM Lifter 🟡 Medium Probability → Shop Engine Valve Lifter The 6.2L L94 V8 engine's Active Fuel Management (AFM) system uses special deactivating lifters on cylinders 1, 4, 6, and 7 that are a very common failure point. A collapsed or stuck lifter will prevent the valve from opening, causing a complete loss of compression and a persistent misfire on that cylinder.
   How to confirm: This is a more advanced diagnosis. It often starts with a characteristic ticking or chirping noise from the engine. A definitive check is to remove the driver's side valve cover and start the engine, observing the rocker arms for cylinder 7. If one of the rocker arms is not moving or has very little travel, the lifter has failed. A running compression test will also show very low or zero compression on cylinder 7. 🎬 Watch: How to diagnose a collapsed AFM lifter misfire
   Typical fix: This is a significant and costly repair. The cylinder head must be removed to replace the failed lifter(s). It is highly recommended to replace all 8 AFM lifters, the four plastic lifter guide trays (GM P/N 12595365), and the Valve Lifter Oil Manifold (VLOM) at the same time. The camshaft is often damaged by the failed lifter and should be inspected and likely replaced. Many owners opt for a full "AFM delete" which involves replacing the AFM lifters with standard lifters, a non-AFM camshaft, and reprogramming the ECM to disable the system. 🎬 See this full AFM delete and camshaft replacement walkthrough
   Est. part cost: $500-$1200 for lifters, gaskets, camshaft, and associated parts for a full AFM repair or delete.
5. Clogged or Faulty Fuel Injector ⚪ Low Probability → Shop Fuel Injector The fuel rail is angled slightly, with the rear (near cylinder 7) being the lowest point. Debris or water from fuel can accumulate at this end over time, eventually clogging the #7 injector.
   How to confirm: Swap the fuel injector from cylinder 7 with another cylinder. If the misfire code follows the injector, it is faulty. You can also listen for the injector's clicking sound with a mechanic's stethoscope to see if it's operating. In some cases, a faulty injector driver in the ECM can mimic a bad injector.
   Typical fix: Replace the faulty fuel injector and its seals. Sometimes, cleaning the injector can resolve the issue.
   Est. part cost: $50-$120

Rare But Worth Checking

• Intake Manifold Gasket Leak: → Shop Engine Intake Manifold 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 test.
• Low Compression (Valves, Piston Rings): Beyond a failed lifter, a bent valve, broken valve spring, worn valve seat, or bad piston rings can cause a loss of compression leading to a misfire. A compression test and cylinder leak-down test would be needed to diagnose this.
• Worn Camshaft Lobe: → Shop Engine Camshaft Even if the lifter roller appears okay, the corresponding camshaft lobe can be worn down, preventing proper valve lift. This will cause a misfire and often a ticking or squeaking noise. The camshaft must be inspected during a lifter replacement job.
🎬 Watch: A cost-effective approach to repairing Escalade lifter tick

Diagnosis Steps

1. Read the code with an OBD-II scanner and confirm P0307. Note any other codes present, like P0300.
2. Check the freeze frame data to understand the engine conditions (RPM, load, temperature) when the misfire occurred.
3. Per TSB #PIP4819A, inspect the spark plug wire for cylinder 7. Ensure it is fully seated on the spark plug and ignition coil and shows no signs of damage.
4. Swap the ignition coil from cylinder 7 with an adjacent, easy-to-access cylinder (like cylinder 5). Clear the codes and run the engine. If the misfire moves to the new cylinder (P0305), the coil is bad.
5. If the misfire remains on cylinder 7, remove and inspect the spark plug. Replace if it appears worn, fouled, or damaged.
6. If ignition parts are good, listen for a distinct ticking, tapping, or squeaking sound from the driver's side of the engine, which strongly indicates a failed lifter or worn camshaft lobe.
7. For a definitive mechanical check, remove the driver's side valve cover. Start the engine and visually inspect the rocker arms for cylinder 7. If a rocker arm is not moving or has significantly less travel, the AFM lifter has failed.
8. If visual inspection is inconclusive, perform a compression test on cylinder 7. A very low or zero reading points towards a mechanical issue like a collapsed AFM lifter or a valve problem.
9. If compression is good, the issue may be fuel-related. Check the fuel injector on cylinder 7 by listening for its operation or swapping it with another cylinder.
10. If the cause is still not found, perform a cylinder leak-down test to pinpoint the source of compression loss or check for vacuum leaks using a smoke machine.

Parts You'll Likely Need

• Ignition Coil (OEM #12611424) — This is one of the most common electrical failure points causing a single-cylinder misfire.
  Trusted brands: ACDelco, Delphi, NGK
  OEM price range: $50-$90
  Aftermarket price range: $30-$60
• Iridium Spark Plug (OEM #41-162) — Spark plugs are a routine maintenance item and a frequent cause of misfires as they wear out.
  Trusted brands: ACDelco, NGK, Denso
  OEM price range: $12-$20
  Aftermarket price range: $8-$15

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 is common during the initial stages of an AFM lifter failure.
• P0011 or P0014 — Camshaft Position timing codes can sometimes appear. TSB PIP5162D suggests inspecting the camshaft actuator solenoid screens for debris, which can be a byproduct of internal engine wear from issues like a failing lifter.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Mentions inspecting and replacing loose spark plug wires for misfire codes on 2010 models.
• 19-NA-219: Provides detailed diagnostic information for engine noises (chirp, squeak, tick) and misfires (P0300-P0308) that may be caused by a worn camshaft lobe, sticking valve, or collapsed AFM lifter.
• PIP5162D: Relates to camshaft position timing codes (P0011/P0014) and advises checking solenoid screens for debris, which can be a symptom of internal engine wear.

Platform-Specific Known Issues

• AFM Lifter Failure is Paramount: → Shop Engine Valve Lifter For the L94 engine, a P0307 code has a significantly higher probability of being a failed Active Fuel Management (AFM) lifter compared to other vehicles. This is the most well-documented, serious, and common major failure on this specific platform. Diagnosis should prioritize ruling this out early.
• AFM Delete as a Common Solution: Due to the high failure rate of the AFM system, many owners and independent shops opt for an "AFM Delete" during repair. This involves replacing the specialized AFM components (camshaft, lifters, VLOM) with standard, more robust non-AFM parts and reprogramming the ECU. This is considered a permanent fix to prevent future lifter failures.
• StabiliTrak Warning Light: A common secondary symptom is the illumination of the "Service StabiliTrak" or traction control warning light. The engine control module detects the power imbalance from the misfire and flags a potential stability issue, which can be confusing. This light often appears concurrently with the flashing check engine light.

Mechanic-Grade Diagnostic Values

• Fuel Injector Resistance — expected: 3.5 - 4.0 Ohms. Failure: A reading significantly higher or lower than the specified range indicates a faulty injector coil.
• Fuel Pressure (at fuel rail) — expected: 85.5 - 88.5 PSI. Failure: Pressure below the minimum specification can cause lean misfires, though it would typically affect multiple cylinders.
• Mode $06 Misfire Count — expected: 0 counts on a healthy cylinder.. Failure: Any count value indicates the ECM has registered misfire events for that specific cylinder, even if it hasn't triggered a CEL yet. This can confirm an intermittent misfire on cylinder 7.

Hidden / Shadow Codes Worth Checking

• Mode $06, Test ID $A7: This refers to the Mode $06 data for Cylinder 7 Misfire Data. It provides raw misfire counts for the current and previous 10 driving cycles. (see via A professional scan tool capable of reading Mode $06 data is required. This data can reveal intermittent misfires on cylinder 7 before they are frequent enough to set a persistent P0307 code.)

Scan Tool Commands That Help

• GM GDS2 / Tech2 or equivalent professional scan tool: Cylinder Power Balance Test — This test is used to confirm a loss of contribution from cylinder 7. The scan tool deactivates each cylinder one by one and measures the drop in RPM. If deactivating cylinder 7 causes little or no RPM drop compared to other cylinders, it confirms it is not contributing power, pointing to a significant ignition, fuel, or mechanical issue.
• GM GDS2 / Tech2 or equivalent professional scan tool: Fuel Injector Balance Test — This command can be used to test if the fuel injector for cylinder 7 is delivering the correct amount of fuel. It helps differentiate between a fuel delivery problem and a spark or compression issue.

Wiring & Ground Locations

• G102 — Located at the left rear of the engine, sometimes described as being on the back of the driver's side cylinder head.. This is the primary ground for all 8 ignition coils. A poor connection here can cause a weak or intermittent spark on any cylinder, including cylinder 7.
• G103 — Located on the front of the right (passenger) side cylinder head.. This is a main ground for the Engine Control Module (ECM). A poor connection can cause erratic sensor readings and misfire detection.
• G104 — Located on the left rear corner of the engine, mounted to the left (driver's side) cylinder head. A ground strap connects from here to the firewall.. This provides a critical ground path from the engine block (where cylinder 7 is) to the vehicle chassis. A corroded or broken strap can cause various electrical issues, including misfires.

Real Owner Repair Stories

• Chevrolet Forum user (2011 Chevrolet Silverado 5.3L (similar engine architecture)) — Sudden onset of P0307, StabiliTrak/TC lights on.
  ❌ Tried (didn't work) Replacing the spark plug and ignition coil for cylinder 7.
  ✅ What actually fixed it The issue was debris and/or water that had collected at the rear of the fuel rail, clogging the #7 injector. The fix was to remove and clean the fuel rail and replace the #7 fuel injector and its O-rings.
• YouTube video by '87SSBoi' (2007 Chevrolet Tahoe 5.3L with P0307 (similar AFM engine)) — Persistent P0307 misfire on cylinder 7.
  ❌ Tried (didn't work) Standard ignition and fuel system checks.
  ✅ What actually fixed it The cause was a collapsed AFM lifter on cylinder 7. The diagnosis was confirmed by removing the valve cover and observing that the rocker arm for that cylinder was not moving. The repair involved replacing the lifters and camshaft.

OEM Part Supersession History

• 12571595, 12619820, 12639516 → 12698946 (current GM PN for AFM/DOD lifter) — GM has updated the AFM lifter design over the years to improve reliability.
  Heads up: The newest DFM (Dynamic Fuel Management) lifter, part number HL-7025 from Elgin (GM 12698946), is backward compatible with older AFM applications. However, the original AFM lifter (HL-7011) will ONLY fit AFM applications and not newer DFM engines.
• 12589225 (common VLOM part number) → Not specified, but multiple revisions exist. — Updates to improve reliability and address solenoid failures.
  Heads up: When replacing failed AFM lifters, it is critical to inspect and often replace the Valve Lifter Oil Manifold (VLOM) as faulty solenoids or clogged screens in the VLOM can cause repeat lifter failure.