Can I drive with code P0308?

⛔ STOP NOW if flashing / ⚠️ Diagnose soon if steady

How much does it cost to fix code P0308?

Repair costs typically range from $50 to $1500 depending on the root cause, vehicle make/model, and whether you use a dealer or independent shop.

OBD2 Code P0308: Cylinder 8 Misfire Detected

Reviewed by ASE Certified Mechanics · Last updated July 20, 2026

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Quick Answer

P0308 = Cylinder 8 Misfire Detected
Severity: Check Soon · System: Powertrain · ⛔ Do NOT continue driving

⚠️ STOP DRIVING — This code indicates a critical safety issue. Continuing to operate the vehicle may cause engine damage or safety hazard. Pull over safely and diagnose before continuing.

The P0308 code means Cylinder 8 Misfire Detected. Estimated repair cost: $50 – $1500.

⛔ STOP IMMEDIATELY if Check Engine Light is flashing. If steady: drive gently to a repair shop within 1-2 days.

📋 Diagnostic Reference

OBD2 Code	`P0308`
Category	Powertrain
Severity	Check Soon
Repair Cost	$50 – $1500
Can You Drive?	⛔ STOP NOW if flashing / ⚠️ Diagnose soon if steady

🔍 Symptoms

Engine vibration
Check Engine Light on or flashing
rough idle
power loss
unburned fuel smell

⚠️ Most Likely Causes (in order of probability)

Faulty spark plug cylinder 8
Bad ignition coil
Clogged fuel injector
Valve train issue
Low compression

🛠️ Diagnostic Procedure

Step 1: Stop if CEL flashing

Stop if CEL flashing

Step 2: Swap coil from cylinder 8 to another — if misfire moves, replace coil

Swap coil from cylinder 8 to another — if misfire moves, replace coil

Step 3: Check spark plug condition

Check spark plug condition

Step 4: Test fuel injector

Test fuel injector

Step 5: Compression test

Compression test

🔧 DIY Diagnosis: Step-by-Step

Follow this diagnostic flow for P0308 (Misfire & Ignition / Crank-Cam Position Sensors). Start at Step 1 and work your way down — the most likely fixes are listed first.

If the Check Engine Light is FLASHING, stop driving immediately — this means catalytic converter damage is occurring right now
Check for cylinder-specific misfire codes (P0301–P0308) to identify which cylinder(s) are affected
Remove and inspect spark plugs — look for fouling, cracking, excessive gap, or oil contamination
Swap ignition coils between cylinders — if the misfire moves to the new cylinder, the coil is bad
Smoke test the intake for vacuum leaks, especially near the intake manifold gasket
If plugs, coils, and vacuum are all good, perform a compression test to check for internal engine damage

📊 Common Causes & Repair Costs

For P0308, here are the most likely root causes ranked by how often mechanics see them, plus typical repair costs for each.

Rank	Cause	Frequency	Typical Cost
#1	Worn or fouled spark plugs	35%	—
#2	Failed ignition coil	25%	—
#3	Vacuum leak	15%	—
#4	Clogged or failed fuel injector	12%	—
#5	Crankshaft or camshaft position sensor failure	8%	—
#6	Timing chain/belt issue or low compression	5%	—

Category Repair Cost Range (Misfire & Ignition / Crank-Cam Position Sensors)

DIY / Best Case:	$50
Independent Shop:	$300
Dealer / Worst Case:	$1500

Costs include parts + labor. Actual price varies by make, model, and your location.

🚨 Address Immediately

Can you drive? Limited — A steady Check Engine Light with misfire means drive gently to a shop. A FLASHING CEL means pull over and stop — you risk destroying the catalytic converter. Do not drive at highway speeds with an active misfire.

ASE Certified Review: This diagnostic guide has been reviewed by an ASE-certified master technician. Diagnostic steps follow industry best practices per SAE J1979 and OEM service procedures. Always verify with a qualified mechanic before performing repairs.

Technician's Notes: P0308 is specific to V8 engines. Common on Ford 5.4L Triton and Chevy 5.3L Vortec. On Ford Triton engines, the coil-on-plug design makes coil swap testing easy.

Estimated Repair Cost

Typical repair: $50–$1500 (Parts + Labor) · Costs vary by make/model and location

🔌 Don't Pay $150 for a Code Read — Diagnose It Yourself

Dealerships charge $100-$200 just to scan your car and read the code. A $20 Bluetooth OBD2 scanner gives you the same information in 30 seconds — and it works with free apps on your phone. Read and clear codes yourself before deciding if you need a mechanic.

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Affiliate disclosure: We may earn a commission at no extra cost to you.

Data Sources: Diagnostic information compiled from SAE J1979 OBD2 standards, OEM service manuals, and ASE master technician field experience. Reviewed for technical accuracy. Repair cost ranges are national estimates and vary by location. Always verify with a qualified mechanic.

❓ Frequently Asked Questions

Can I drive with a misfire code (P03xx)?

A steady CEL misfire: drive gently to a repair shop within a day or two. A FLASHING CEL: pull over immediately and have the vehicle towed. Continuing to drive with a flashing CEL will destroy your catalytic converter.

How much does it cost to fix a misfire?

Spark plugs: $50–$150 (full set). Ignition coil: $50–$120 each. Vacuum leak repair: $50–$200. Fuel injector: $100–$400. Major repairs (timing chain, compression): $500–$2,000+.

What's the difference between P0300 and P0301?

P0300 means random or multiple cylinders are misfiring — the problem isn't isolated to one cylinder. P0301–P0308 point to a specific cylinder, making diagnosis much easier.

Can bad gas cause a misfire code?

Yes, contaminated or old gasoline can cause misfires, especially if water is present. Try adding fuel system cleaner and filling up with fresh premium fuel from a top-tier station.

Can I just replace one spark plug or coil?

Technically yes, but it's best practice to replace all spark plugs at the same time since they wear evenly. For coils, you can replace just the failed one, but keep in mind the others may fail soon.