🧭 Diagnostic Flowchart 🎬 Helpful Videos 🛍️ Shop This Part

P0305 on 2020-2025 Hyundai Palisade: Cylinder 5 Misfire Causes and Fixes

P0305 on a Hyundai Palisade means cylinder 5 is misfiring. The most common cause is a failed ignition coil or a worn spark plug. This is a difficult DIY repair because cylinder 5 is on the rear bank against the firewall, requiring intake manifold removal. Expect a shop to charge between $500 and $900 for the repair.

17 minutes to read 2020-2025 Hyundai Palisade

Most Likely Cause

Failed Ignition Coil

Difficulty

5/5

Est. Time

3.8 hrs

DIY Doable?

🔧 Shop

Shop Labor

$500 – $900

Parts Price

$150 – $450

⚠️ Drivable, but... — Driving is not recommended, especially if the check engine light is flashing. A persistent misfire allows unburnt fuel into the exhaust, which can quickly overheat and damage the expensive catalytic converter.

Key Takeaways

P0305 signifies a misfire in cylinder 5, which is on the hard-to-reach rear bank of the engine.
The most likely cause is a bad ignition coil, followed by a worn spark plug.
Due to the high labor cost of removing the intake manifold, it is critical to replace all three rear coils and all six spark plugs at the same time.
Owners of 2024 models must check for Recall 255 regarding defective valve springs before attempting any repairs.
Do not drive with a flashing check engine light, as this can quickly lead to expensive catalytic converter damage.

The trouble code P0305 indicates that your Palisade's engine computer (PCM) has detected a misfire in cylinder number five. A misfire happens when the fuel and air mixture in the cylinder fails to ignite properly at the correct time. The PCM monitors the rotational speed of the crankshaft via the crankshaft position sensor. When it detects a speed loss from cylinder 5's power stroke compared to the other cylinders, it triggers the Check Engine Light and stores the P0305 code.

What's Unique About the 2020-2025 Hyundai Palisade

The key challenge with a P0305 code on the Palisade's 3.8L V6 is the location of cylinder 5. It is on the rear cylinder bank (Bank 1), which is positioned against the firewall. Accessing the ignition coil and spark plug is not possible without first removing the entire upper intake manifold, making this a significantly more labor-intensive and complex job than a misfire on the front bank. Because of the high labor cost, the standard recommendation is to replace all three ignition coils and spark plugs on the rear bank (cylinders 1, 3, and 5) at the same time.

Professional service recommended: Accessing cylinder 5 requires the removal of the upper intake manifold, which is a complex and time-consuming job (rated 5/5 difficulty) that is best left to experienced technicians.

Symptoms You May Notice

Rough idling or engine vibrations
Hesitation or stumbling during acceleration
Reduced engine power
Flashing Check Engine Light (indicates a severe misfire)
Poor fuel economy
Fuel smell from the exhaust

⚠️ Don't Waste Money on the Wrong Fix

Replacing only the spark plug in cylinder 5 without replacing the ignition coil, or vice-versa. Given the high labor cost, it's prudent to replace both, along with the other rear bank coils and plugs.
Assuming a fuel system problem (like a bad fuel pump) when it's a single-cylinder misfire. A fuel pump issue would typically affect multiple cylinders or cause random misfire codes (P0300).
Overlooking a vacuum leak from a reused or improperly installed intake manifold gasket after a previous repair, leading to a repeat of the P0305 code.

Most Likely Causes

Failed Ignition Coil 🔴 High Probability → Shop Ignition Coil Ignition coils are a common failure item on modern engines due to constant exposure to heat and vibration. Forum members and technicians report coil failure as a primary cause for single-cylinder misfires on this platform. A Reddit user with a 2021 Palisade confirmed a bad #5 coil was the cause of their P0305 code.
How to confirm: The most definitive test is to swap the ignition coil from cylinder 5 with an easily accessible cylinder on the front bank (e.g., cylinder 2). This requires removing the intake manifold. If the code changes to P0302 after clearing codes and driving, the coil is faulty.
Typical fix: Replace the failed ignition coil. It is highly recommended to replace all three coils on the rear bank (cylinders 1, 3, 5) at the same time due to the labor involved in accessing them.
Est. part cost: $50-$100 per coil
Worn or Fouled Spark Plug 🟡 Medium Probability → Shop Spark Plug Spark plugs are a standard maintenance item. While modern iridium plugs have a long life, they can still fail or become fouled by carbon deposits or oil, especially on GDI engines which are known for carbon buildup on intake valves.
How to confirm: After removing the intake manifold and ignition coil, inspect the spark plug for wear, damage, or fouling (black, sooty, or oily deposits).
Typical fix: Replace the spark plug in cylinder 5. As with the ignition coils, it is strongly recommended to replace all six spark plugs at the same time to avoid repeating the labor-intensive intake manifold removal.
Est. part cost: $15-$30 per plug
Clogged or Faulty Fuel Injector ⚪ Low Probability → Shop Fuel Injector The Lambda II is a Gasoline Direct Injection (GDI) engine, and while generally reliable, the injectors can be susceptible to carbon buildup over time which can affect their spray pattern and lead to misfires. This is a less common cause for a single-cylinder misfire compared to ignition components.
How to confirm: This is more difficult to diagnose. It involves checking fuel trims with a scan tool and potentially swapping injectors between cylinders, which is a labor-intensive job requiring intake manifold removal.
Typical fix: Clean or replace the fuel injector for cylinder 5. This also requires intake manifold removal.
Est. part cost: $80-$150 per injector

Rare But Worth Checking

Fractured Engine Valve Spring (Certain 2024 Models): Hyundai issued Recall 255 (NHTSA ID: 24V-106) for a batch of 2024 Palisades built between August 21, 2023, and October 12, 2023. Defective valve springs can fracture due to fatigue, causing a misfire, sudden loss of power, and potentially a hole in the engine block, which increases the risk of a crash or fire. The fix is a complete engine sub-assembly replacement performed by a dealer at no charge.
Intake Manifold Gasket Leak: → Shop Engine Intake Manifold When the intake manifold is removed for service, the gaskets must be replaced. Reusing old gaskets or improperly installation can cause a vacuum leak near cylinder 5, disrupting the air-fuel ratio and causing a misfire. A recurring P0305 after a repair is often due to a pinched or improperly seated gasket.
Low Engine Compression: This indicates an internal mechanical engine problem, such as worn piston rings, a leaking head gasket, or a valve sealing issue. A compression test on cylinder 5 is required to diagnose this. It is uncommon on a newer vehicle but possible, especially if the engine has overheated or has high mileage.
Intake Valve Carbon Buildup: As a GDI engine, the Lambda II V6 is prone to carbon accumulation on the intake valves over time (typically >60,000 miles), as fuel does not wash over them. Severe buildup can restrict airflow to a specific cylinder, causing misfires. The fix is a professional 'walnut blasting' intake cleaning service.

Diagnosis Steps

For 2024 models, immediately check the vehicle's VIN for Hyundai Recall 255 (NHTSA 24V-106) before any diagnosis. If the vehicle is part of the recall, contact a Hyundai dealer for a free engine sub-assembly replacement.
For early 2020 models experiencing misfires on cold starts, inquire with a dealer about a potential ECM software update. The sister vehicle, Kia Telluride, had a TSB (ENG228) for this issue which addressed overly sensitive misfire detection.
Confirm the P0305 code is present using an OBD-II scanner. Check freeze-frame data to see the engine conditions when the misfire occurred.
Plan for intake manifold removal. This is a complex job. Purchase new upper intake manifold gaskets, as they are single-use.
Once the manifold is off, access cylinder 5 (rear bank, driver's side). Swap the ignition coil from cylinder 5 with the coil from cylinder 2 (front bank, passenger's side).
While the manifold is off, it is highly recommended to replace all three ignition coils and all six spark plugs to avoid future high labor costs.
Consider inspecting the intake valves for heavy carbon buildup with a borescope while the manifold is removed.
Reinstall the intake manifold with new gaskets and torque all bolts to factory specifications.
Clear the trouble codes with the scanner and perform a test drive.
If the code returns as P0302, the original ignition coil from cylinder 5 is faulty. If the code remains P0305, the issue is likely the spark plug, fuel injector, or a mechanical problem in cylinder 5.

Parts You'll Likely Need

Ignition Coil (Rear Bank) (OEM #27310-3L000) — This is the most common part to fail and cause a P0305 misfire. Cylinder 5 is on the rear bank.
Trusted brands: Hyundai (OEM), NGK, Denso
OEM price range: $95-$140
Aftermarket price range: $50-$100
Iridium Spark Plug (OEM #18849-11070) — A worn or fouled spark plug is the second most likely cause. It should always be replaced when the labor-intensive job of removing the intake manifold is performed.
Trusted brands: Hyundai/Kia (OEM), NGK
OEM price range: $25-$35
Aftermarket price range: $15-$30
Upper Intake Manifold Gasket Set (OEM #29215-3CFA1) — These are single-use gaskets that are required to be replaced anytime the intake manifold is removed to prevent vacuum leaks. The previous part number was 29215-3CFA0.
Trusted brands: Hyundai (OEM), Fel-Pro, Mahle
OEM price range: $30-$50
Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

P0300 — If the misfire is intermittent or other cylinders are also misfiring, a P0300 (Random/Multiple Cylinder Misfire) code may accompany P0305.
P0301, P0303 — If the root cause is affecting the entire rear bank (e.g., a vacuum leak from the intake manifold gasket on that side), you may see misfire codes for the other rear cylinders as well.

Technical Service Bulletins (TSBs) & Recalls

Kia TSB ENG228: Addresses overly sensitive misfire detection on early 2020 Kia Tellurides, potentially applicable to Palisades.
Hyundai TSB 21-01-003H / 21-BD-003H: Addresses wind noise from the front door/mirror area on 2020-2021 models.
Hyundai TSB 24-01-039H-2: Provides the service procedure for replacing the engine sub-assembly under Recall 255.

Platform-Specific Known Issues

Recall 255 (NHTSA 24V-106): A specific batch of 2024 Palisades are recalled for defective engine valve springs that can fracture, causing misfires and potential engine failure. The remedy is an engine sub-assembly replacement.
ECM Software Sensitivity (Early 2020 Models): The platform-mate Kia Telluride had a TSB (ENG228) for early 2020 models where the ECM's misfire detection was too sensitive, especially on cold starts. A software update at the dealer could resolve the issue without replacing parts. It is worth inquiring about a similar update for the Palisade.

Diagnostic Flowchart

The P0305 code indicates a misfire on Cylinder 5 (Rear Bank, Driver's Side). Because this cylinder is located under the intake manifold, diagnosis requires a systematic approach to avoid unnecessary labor.

Check your VIN for Hyundai Recall 255 (NHTSA 24V-106). Is your vehicle included in the engine valve spring recall?

→ STOP. Do not attempt DIY repair. Contact a Hyundai dealer immediately for a free engine sub-assembly replacement under Recall 255.

Is this an early 2020 model experiencing the misfire primarily during cold starts?

→ Inquire with a dealer about an ECM software update. Platform-mate Kia Telluride TSB ENG228 addresses overly sensitive misfire detection that can be fixed via software without replacing parts.

To test the hardware, you must remove the intake manifold. Once removed, swap the Cylinder 5 ignition coil with Cylinder 2 (Front Bank). Clear codes and drive. What is the result?

→ The ignition coil is faulty. Replace the coil. Recommendation: Replace all three rear bank coils (1, 3, 5) and all six spark plugs while the manifold is removed to save on future labor.

Remove and inspect the Cylinder 5 spark plug. Does it show heavy carbon fouling, oily deposits, or a cracked insulator?

→ Replace the spark plugs. Note: If the plug is oily, check for excessive oil consumption (a known issue on 2020-2022 models). If heavily carbon-fouled, perform a GDI intake valve cleaning.

Check fuel trims with a scan tool. Are long-term fuel trims significantly positive (>10%) or is there a fuel smell from the exhaust?

→ The GDI fuel injector for Cylinder 5 is likely clogged or faulty. Replace the injector and inspect intake valves for carbon buildup while the fuel rail is accessible.

→ Perform a compression and leak-down test on Cylinder 5. If mechanical integrity is low, the engine may require internal repair or sub-assembly replacement as seen in high-mileage Lambda II oil consumption cases.