Fix P0308: Cylinder 8 Misfire With iCarsoft CR MAX BT
If your vehicle shakes violently, loses power, or the check engine light flashes with OBD2 code P0308, you’re dealing with a critical cylinder misfire issue. P0308 signals “Cylinder 8 Misfire Detected”—a fault where the 8th cylinder fails to ignite fuel properly, disrupting engine balance and performance. Ignore it, and you’ll face severe engine damage (e.g., bent valves, damaged pistons), increased fuel consumption, or even catalytic converter failure.
But diagnosing P0308 doesn’t have to mean costly dealership visits. In this guide, we’ll break down P0308 in plain English: what it is, common causes, red-flag symptoms, and how the iCarsoft CR MAX BT diagnostic tool (with wireless Bluetooth) simplifies troubleshooting for DIYers and mechanics. Plus, we’ll share real customer reviews, 8 FAQs, and show you how to fix P0308 at home. Let’s get your engine running smoothly again!
What Is OBD2 Code P0308?
P0308 is a standard OBD2 diagnostic trouble code defined as “Cylinder 8 Misfire Detected”. In multi-cylinder engines (typically V6/V8 or boxer engines), each cylinder relies on a precise combination of fuel, air, and spark to ignite. The Engine Control Unit (ECU) monitors engine vibrations and sensor data—when it detects that Cylinder 8 isn’t contributing to power (i.e., no combustion), it triggers P0308.
This code is most common in vehicles with 8-cylinder engines (e.g., Ford F-150, Chevrolet Silverado, BMW X5, Mercedes-Benz GLE) but can appear in modified 6-cylinder engines with aftermarket cylinder configurations. A misfire in Cylinder 8 creates unbalanced engine operation, leading to rough running and potential long-term damage.
Top 5 Causes of P0308
1. Faulty Ignition System Components
The #1 culprit—worn spark plugs, damaged ignition coils, or faulty spark plug wires prevent proper spark in Cylinder 8.
2. Clogged/Faulty Fuel Injector
A blocked or malfunctioning fuel injector fails to deliver the right amount of fuel to Cylinder 8, causing incomplete combustion.
3. Low Cylinder Compression
Mechanical issues (e.g., worn piston rings, damaged valves, head gasket leaks) reduce compression in Cylinder 8, preventing ignition.
4. Sensor Malfunctions
Faulty oxygen (O2) sensors, mass airflow (MAF) sensors, or crankshaft position sensors send incorrect data to the ECU, disrupting fuel/spark timing.
5. Vacuum Leaks
Leaks in the intake manifold or vacuum hoses near Cylinder 8 upset the air-fuel mixture, leading to misfires.
Common Symptoms of P0308
Don’t ignore these warning signs—they mean P0308 is damaging your engine:
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Illuminated check engine light (often flashing, indicating a severe misfire).
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Violent engine shaking or rough idling (felt in the steering wheel or cabin).
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Reduced engine power and hesitation during acceleration.
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Increased fuel consumption (unburned fuel is wasted).
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Strong exhaust odor (raw fuel) or black smoke from the tailpipe.
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Catalytic converter overheating (risk of permanent damage if unaddressed).
Why the iCarsoft CR MAX BT Is Your Best Tool for P0308
Basic OBD scanners can read P0308, but they can’t pinpoint the root cause (e.g., spark plug vs. injector) or test components. The iCarsoft CR MAX BT—equipped with wireless Bluetooth and advanced engine diagnostics—gives you professional-grade tools to isolate Cylinder 8 issues and fix them at home, no tangled cables required.
Key Features That Simplify P0308 Troubleshooting:
Cylinder-Specific Diagnostics
Reads P0308 and detailed subcodes (e.g., “Cylinder 8 Misfire During Acceleration”) to target the exact issue.
Bluetooth Wireless Connectivity
Syncs with iOS/Android devices for cable-free operation—perfect for accessing hard-to-reach ignition coils.
Live Data Streaming
Monitors real-time data for Cylinder 8 (ignition coil voltage, fuel injector pulse width, compression readings) to confirm faulty components.
Bidirectional Control
Tests ignition coils and fuel injectors by sending commands—critical for ruling out electrical vs. mechanical failures.
Multi-Brand Compatibility
Works with 60+ global brands (Ford, Chevrolet, BMW, Mercedes-Benz, Toyota, and more).
Intuitive Mobile App
Step-by-step prompts, AutoVIN identification, and multilingual support (15 languages) make it beginner-friendly.
Lifetime Free Updates
Stays compatible with new 8-cylinder models and updated diagnostic protocols.
Pro Tip: The CR MAX BT’s “Misfire History” feature logs when Cylinder 8 misfires (e.g., at idle, high RPMs), helping you narrow down causes like vacuum leaks (idle misfires) or faulty ignition coils (high-RPM misfires).
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Real Customer Reviews: How the CR MAX BT Fixed P0308
“I got P0308 on my 2019 Ford F-150 (5.0L V8) and was quoted $500 by the dealership (ignition coil + labor). Bought the iCarsoft CR MAX BT, paired it with my iPhone, and scanned in 60 seconds—confirmed Cylinder 8’s ignition coil was faulty. Replaced it for $70 and used the tool to clear the code. My truck runs smoother than ever, and I saved over $430! Bluetooth makes it so easy to test coils without disconnecting them.”
— Tyler M., Truck Owner
“As a small garage mechanic, I see P0308 often in V8 luxury vehicles. The CR MAX BT has fixed it on BMW X5s, Mercedes GLEs, and Chevrolet Silverados. The live data streaming lets me compare Cylinder 8’s performance to other cylinders—no guesswork. Wireless sync is seamless, and the app’s injector tests save me hours. Worth every penny for professionals and DIYers!”
— Sophia L., Independent Mechanic
“I’m not mechanically savvy, but the CR MAX BT made P0308 simple. Paired it with my Android phone, followed the prompts, and found a clogged fuel injector in Cylinder 8. Cleaned it with $15 injector cleaner and cleared the code—my 2017 Toyota Sequoia no longer shakes. Avoided a $800 shop bill. The Bluetooth feature means no tangled cables—total game-changer!”
— David K., Family Commuter
8 FAQs About P0308 & the iCarsoft CR MAX BT
1. Can I Drive With P0308?
No—flashing check engine light means a severe misfire that can damage the catalytic converter or engine. If the light is solid, short trips (under 5 miles) are risky—fix it immediately.
2. How Much Does It Cost to Fix P0308?
Cost varies: Spark plugs/ignition coils cost $50–$200 (parts); fuel injectors cost $100–$300; mechanical repairs (compression issues) cost $500–$2,000+. The CR MAX BT helps you avoid overpaying for unnecessary work.
3. Will the CR MAX BT Work With My 8-Cylinder Vehicle?
The CR MAX BT covers 60+ global brands, including Ford, Chevrolet, BMW, Mercedes-Benz, Toyota, and Dodge 8-cylinder models. Check the official compatibility list for your make/model/year.
4. How Do I Use the CR MAX BT to Diagnose P0308?
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Download the iCarsoft app and pair the tool with your phone via Bluetooth.
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Plug the CR MAX BT into your vehicle’s OBDII port (under the dashboard).
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Turn on the ignition (don’t start the engine) → Select “Engine System” → “Read DTCs”—the app displays P0308 and a description.
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Go to “Live Data” → Monitor Cylinder 8’s ignition coil voltage and injector pulse—erratic readings confirm the issue.
5. Can the CR MAX BT Clear P0308 Permanently?
Yes! After fixing the root cause (e.g., replacing the ignition coil), select “Clear DTCs” in the app. Test drive to confirm no reoccurrence—use live data to verify Cylinder 8 is firing properly.
6. Do I Need Mechanical Experience to Use the CR MAX BT?
No—its user-friendly app, AutoVIN identification, and step-by-step prompts make it beginner-friendly. Multilingual support (15 languages) adds convenience.
7. What If P0308 Comes Back After Clearing It?
If the code returns, the root cause (e.g., low compression or hidden vacuum leak) wasn’t fixed. Use the CR MAX BT’s bidirectional tests and cylinder balance data to troubleshoot further.
8. Does the CR MAX BT Offer Other Misfire-Related Functions?
Yes—beyond P0308, it can diagnose misfires in all cylinders (P0300–P0307, P0309+), test ignition coils, monitor fuel pressure, and diagnose related codes like P0358 (Ignition Coil H Circuit Malfunction) or P0208 (Fuel Injector 8 Circuit Malfunction).
Final Thoughts: Don’t Let P0308 Damage Your 8-Cylinder Engine
OBD2 code P0308 is a critical but fixable issue—with the right tool. The iCarsoft CR MAX BT combines wireless Bluetooth convenience with professional-grade engine diagnostics, letting you pinpoint Cylinder 8’s problem and fix it at home without dealership markups.
Whether you’re a truck owner, luxury vehicle driver, or mechanic, the CR MAX BT’s durability, multi-brand coverage, and lifetime updates make it a long-term investment. Fix P0308, restore engine balance, and protect your vehicle from costly damage—all with one wireless tool.
Ready to tackle P0308 head-on? Click below to get the iCarsoft CR MAX BT and unlock seamless, cable-free misfire diagnostics!
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Have questions about P0308 or the CR MAX BT? Drop a comment below—we’re here to help!
Disclaimer: This guide is for informational purposes only. Always consult your vehicle’s owner’s manual or a certified mechanic before major repairs. iCarsoft is not responsible for damage from improper tool use.
