P0301 on 2011-2013 Chevrolet Camaro: Cylinder 1 Misfire Causes and Fixes

What's Unique About the 2011-2013 Chevrolet CAMARO

Platform-specific issues vary by engine. For the 6.2L V8s, a key issue highlighted by General Motors is loose spark plug wires. A Technical Service Bulletin (TSB #PIP4819A) was issued mentioning that P030x misfire codes could be caused by spark plug wires that need inspection and replacement if found to be loose. For the L99 V8 with Active Fuel Management (AFM), a P0301 code accompanied by a ticking noise is a strong indicator of a collapsed AFM lifter, a well-documented and serious mechanical failure. The 3.6L V6 (LFX) uses a coil-on-plug design without traditional wires, so the TSB does not directly apply; however, an improperly seated coil boot can cause a similar issue. Early LFX engines (2012) can also be prone to timing chain issues carried over from the previous LLT engine design, which can lead to misfires.

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
• Hesitation or stumbling during acceleration
• Noticeable loss of engine power
• Solid or flashing Check Engine Light
• Smell of unburned gasoline from the exhaust
• The "Service StabiliTrak" message may appear on the driver information center
• Audible ticking or tapping sound from the engine bay, especially on L99 V8s, which could indicate a lifter issue

Most Likely Causes

1. Loose/Faulty Spark Plug Wire (V8) or Ignition Coil Boot (V6) 🔴 High Probability A specific GM TSB (PIP4819A) for 2011 V8 models explicitly calls out inspecting and replacing loose spark plug wires for P030x codes. The V6 LFX is coil-on-plug, but a loose or damaged boot can create the same effect.
   How to confirm: For V8s, visually inspect the cylinder 1 spark plug wire. Ensure it is securely clicked onto both the ignition coil and the spark plug. Check for arcing (white marks) or damage. For the V6, ensure the coil pack is fully seated on the spark plug.
   Typical fix: Replace the spark plug wire set (V8) or the single ignition coil boot (V6). It is best practice to replace all wires/boots at the same time and apply dielectric grease.
   Est. part cost: $40-$100 (V8 Wire Set), $10-$20 (V6 Boot)
2. Worn or Fouled Spark Plug 🔴 High Probability Spark plugs are a routine maintenance item and a very common cause of single-cylinder misfires as they wear out.
   How to confirm: Remove the spark plug from cylinder 1. Inspect it for wear (rounded electrode), carbon fouling (black, sooty), oil fouling (wet, black), or damage to the ceramic insulator. A cracked insulator is a definitive sign of failure.
   Typical fix: Replace the spark plug in cylinder 1. It is highly recommended to replace all spark plugs 🎬 Watch: Step-by-step spark plug replacement for V8 Camaros. at the same time to ensure even performance. Always use the specified OEM plugs.
   Est. part cost: $10-$25 per plug
3. Faulty Ignition Coil 🟡 Medium Probability Ignition coils fail from heat cycles and vibration. It's a common failure point for modern ignition systems.
   How to confirm: Swap the ignition coil from cylinder 1 with another cylinder (e.g., cylinder 3 on the same bank). Clear the codes and drive the vehicle. If the code changes to P0303, the coil is faulty.
   Typical fix: Replace the faulty ignition coil.
   Est. part cost: $30-$70
4. Clogged or Faulty Fuel Injector ⚪ Low Probability Direct injection (LFX) and port injection (LS3/L99) injectors can become clogged with deposits, disrupting the fuel spray pattern and causing a misfire.
   How to confirm: A mechanic can perform a fuel injector balance test. A DIY method is to listen to the injector with a mechanic's stethoscope; it should have a consistent, audible clicking sound. You can also swap injectors between cylinders to see if the misfire follows, though this is more labor-intensive.
   Typical fix: Replace the faulty fuel injector. Cleaning is sometimes an option, but replacement is often more reliable.
   Est. part cost: $50-$150

Rare But Worth Checking

• Collapsed AFM Lifter (L99 V8 Only): A major known issue on the L99 engine with Active Fuel Management (AFM). A lifter can become mechanically stuck or collapsed, causing the valve to stop operating. This typically presents with a P0300 or a single-cylinder misfire code (like P0301, as cylinder 1 is an AFM cylinder) and a distinct ticking or squeaking noise. 🎬 See how to diagnose a failing AFM lifter. This is a serious mechanical failure requiring removal of the cylinder head to replace the lifters. Many owners opt to perform an 'AFM delete' at this time.
• Low Engine Compression: If ignition and fuel checks do not reveal the problem, a mechanical issue could be the cause. This can be due to a worn piston ring, a leaking valve, a damaged cylinder head gasket, or a worn camshaft lobe. A compression test is required to diagnose this.
• Stretched Timing Chain (LFX V6): The 2012 LFX engine's timing chain design was an area of concern, carried over from the previous LLT engine. While more often associated with codes like P0008, significant chain stretch can alter cam timing enough to cause misfires. This is less common on 2013+ models which received an improved chain design.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0301 is present.
2. Note if the Check Engine Light is steady or flashing. A flashing light indicates a severe misfire that could damage the catalytic converter.
3. Listen for engine noises. A persistent ticking on a V8 could point towards a lifter issue, which is a more serious repair.
4. (V8 Models) Inspect the spark plug wire for cylinder 1. Per TSB #PIP4819A, ensure it is not loose and shows no signs of damage or arcing.
5. Swap the ignition coil from cylinder 1 to another cylinder on the same bank (e.g., cylinder 3). Clear the codes, run the engine, and see if the misfire code moves to P0303. If it does, the coil is bad.
6. If the code remains P0301, remove and inspect the spark plug from cylinder 1. Look for wear, fouling, or damage. Replace if necessary, preferably as a full set.
7. If the plug, wire/boot, and coil are good, the next step is to check the fuel injector. Listen for a steady clicking sound with a stethoscope. Swapping injectors is a more definitive but labor-intensive test.
8. If all ignition and fuel components for cylinder 1 are confirmed to be working, perform an engine compression test on cylinder 1 to check for mechanical engine problems like bad rings, valves, or a failed lifter (L99).

Parts You'll Likely Need

• Spark Plug (OEM #12681660 (ACDelco 41-123, supersedes 41-109 for V6), 12621258 (ACDelco 41-162, supersedes 41-110 for V8)) — This is a common wear item and one of the most frequent causes of a single-cylinder misfire. Part numbers have been superseded by GM.
  Trusted brands: ACDelco, NGK
  OEM price range: $15-$25
  Aftermarket price range: $10-$20
• Ignition Coil (OEM #12632479 (ACDelco D521C for V8 & V6)) — A common failure point that is easily diagnosed by swapping its position with another cylinder.
  Trusted brands: ACDelco, Delphi, Denso
  OEM price range: $40-$70
  Aftermarket price range: $25-$50
• Spark Plug Wire Set (V8 Only) (OEM #92242544 (ACDelco 748UU for V8)) — A GM Technical Service Bulletin specifically identifies loose spark plug wires as a cause for this code on V8 models. The V6 LFX engine does not use spark plug wires.
  Trusted brands: ACDelco, MSD
  OEM price range: $60-$90
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent, severe, or begins to affect other cylinders, a P0300 (Random/Multiple Misfire) code may appear alongside P0301. On L99 engines, a P0300 is very common with a failing AFM lifter.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Addresses engine misfires (including P0301) on V8 engines and points to inspecting and replacing loose spark plug wires.
• 15-06-01-002F: While not specific to P0301, this bulletin discusses engine misfires (P0300) and ticking noises caused by mechanically collapsed/stuck AFM lifters, a primary cause for P0301 on L99 engines.

Platform-Specific Known Issues

• L99 V8 Collapsed AFM Lifter: The L99 V8 engine features Active Fuel Management (AFM), which deactivates cylinders (including cylinder 1) to save fuel. The hydraulic lifters used for this system are a known failure point. They can collapse or get stuck, leading to a dead cylinder, a P0301 code, and a characteristic ticking noise. Repair is costly as it requires removing the cylinder head. Many owners elect to replace all AFM components with standard LS3 parts (an 'AFM Delete') during the repair.
• TSB for Loose Spark Plug Wires (V8 Models): GM issued TSB #PIP4819A regarding misfire codes (P0300-P0308) on V8 engines. It advises technicians to inspect for loose-fitting spark plug wires at the coil and plug, as poor retention can cause an intermittent connection and misfires. This makes checking wire fitment a critical first step on V8 Camaros.
• Timing Chain Stretch (2012 LFX V6): The 2012 model year LFX V6 used a timing chain design that was susceptible to premature stretching, an issue carried over from the prior LLT engine. While this typically sets timing correlation codes (e.g., P0008), if the timing becomes sufficiently retarded, it can cause misfires. This was largely resolved in 2013+ models.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Resistance — expected: 0.4 to 2.0 ohms. Failure: A reading outside of this range, or a significant deviation (>10%) from the other coils.
• Ignition Coil Secondary Resistance — expected: 6,000 to 10,000 ohms. Failure: A reading outside of this range suggests a faulty coil winding.
• Fuel Injector Connector Voltage (KOEO) — expected: ~12V (Battery Voltage). Failure: Low or no voltage indicates a problem in the wiring harness or the ECM's power supply to the injector circuit.

Scan Tool Commands That Help

• GDS2 / Tech2: Cylinder Power Balance Test — This function allows a technician to disable one cylinder at a time (by cutting fuel) and observe the corresponding drop in engine RPM. If disabling cylinder 1 causes little or no RPM drop compared to other cylinders, it confirms that cylinder 1 is not contributing power, helping to isolate the fault without major disassembly.
• GDS2: Automated Injector Balance Test (GDI Engines) — For the LFX V6 with direct injection, this automated test disables each injector and measures the resulting pressure drop in the fuel rail. It can identify a clogged or malfunctioning injector by comparing the pressure drop values across all cylinders.

Wiring & Ground Locations

• Engine Harness Grounds (V8) — Key grounds are located on the back of both the driver's side and passenger's side cylinder heads.. A loose or corroded ground on the cylinder head can cause erratic behavior for the ignition coils and injectors mounted on that bank, leading to misfires. The ground on the driver's side head is particularly relevant for a P0301.
• Engine Harness Chafe Point (Driver's Side) — The main engine harness can rub against the ECM/TCM bracket, the driver's side upper control arm, and the shock tower.. Chafing can expose and short wires within the harness, including the ignition coil control or fuel injector control wires for cylinder 1, causing an intermittent or persistent misfire. A GM service bulletin addresses this by instructing technicians to re-route and protect the harness.
• Engine Harness Chafe Point (Passenger Side / Headers) — On V8 models, especially with aftermarket headers, the wiring harness running along the passenger side of the engine can come into contact with hot exhaust tubes.. While P0301 is on the driver's side, this is a known issue for general misfires. A similar issue on the driver's side could melt the wiring for the cylinder 1 coil or injector, causing a direct short and misfire.

Real Owner Repair Stories

• Camaro5 Forums user 'Iam Broke' (5th Gen Camaro SS (V8)) — Car fell on its face, check engine light with multiple codes, then no-start and zero fuel pressure.
  ❌ Tried (didn't work) Initial taping of harness was a temporary fix.
  ✅ What actually fixed it The user discovered the main engine wiring harness had melted on an aftermarket header tube, fusing 4-7 wires together. The ultimate fix required repairing the melted section of the harness and securing it away from the heat source.
• Camaro5 Forums user 'its Sparkyyy' (2012 Camaro V6) — Slight misfires on cylinders 1 and 4 when revved high near a shift point.
  ❌ Tried (didn't work) Replaced all spark plugs, replaced injectors for cylinders 1 and 4, swapped ignition coils.
  ✅ What actually fixed it The user's mechanic suspected rusted pins in a large electrical connector near the fuse box as the cause, though the final resolution was not posted in the thread. This points to a wiring or connection issue beyond the component level.

"I Checked Everything" — The Actual Cause

• A smoke test for vacuum leaks may come back clean, but the issue could be a leaking intake manifold gasket. On these engines, a gasket leak might only manifest as a vacuum leak under specific temperature or load conditions, or it could be an internal leak between a runner and a coolant passage (on V6) that a smoke test wouldn't find. Symptoms include a hissing noise, rough idle, and lean codes.

OEM Part Supersession History

• ACDelco 41-109 (V6 Spark Plug) → ACDelco 41-123 — GM periodically updates spark plug designs for improved durability and performance.
  Heads up: The 41-123 is the correct replacement. While some owners have noted slight physical differences, it is the correct, updated part and functions properly.
• ACDelco 41-110 (V8 Spark Plug) → ACDelco 41-162 — Updated design for improved performance and longevity.

Model Year Variations Within This Range

• 2011 vs 2012+: The 2011 model year used the 3.6L LLT V6 engine. In 2012, this was replaced by the 3.6L LFX V6. While similar, the LFX featured updates including an improved timing chain design to address premature stretching issues common on the LLT.
• 2012: Early 2012 LFX engines may still have the older timing chain design from the LLT. GM released updated timing chain kits in April 2012 to be used for service on all 2007-2012 High Feature V6 engines, indicating a mid-cycle improvement.