P0304: Cylinder 4 Misfire Detected
151 vehicles · 21 makes
P0304 is an OBD-II diagnostic trouble code meaning “Cylinder 4 Misfire Detected.” Misfires detected specifically in cylinder 4. This code appears across 151 vehicle models from 21 manufacturers.
Common Causes
Diagnostic Tools
To diagnose P0304, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Vehicles Affected (151)
Intake Valve Carbon Buildup
Ignition Coil Failure
EGR Valve/Cooler Failure
Carbon Buildup on Intake Valves (2.9T Twin-Turbo V6)
Severe Carbon Buildup on Intake Valves (Direct Injection Engines)
Water Pump and Thermostat Failure
Severe Carbon Buildup on Intake Valves (4.0T V8)
Water Pump and Thermostat Housing Coolant Leaks
Direct Injection Carbon Buildup (Intake Valves)
Intake Valve Carbon Buildup (Direct Injection)
Carbon Buildup on Intake Valves (2.0 TFSI Direct Injection)
4.2L V8 Carbon Buildup and High-Rev Issues
Carbon Buildup on Intake Valves (4.0T Twin-Turbo V8)
4.0T Carbon Buildup on Intake Valves
2.7T Ignition Coil Pack Failure Causing Misfires and Flashing Check Engine Light
Coil Pack Failure and Ignition Misfires on 1.8T Engines
PCV Valve Failure (Rough Idle and Oil Consumption)
Severe Carbon Buildup on Intake Valves (Direct Injection)
Severe Carbon Buildup Causing Valve Damage (3.0T TFSI)
Excessive Oil Consumption (2.0 TFSI Engine)
Severe Carbon Buildup on Intake Valves (Direct Injection)
Water Pump Failure (60k Mile Lifespan)
Severe Carbon Buildup on Intake Valves (3.0T)
Carbon Buildup on Intake Valves (Direct Injection)
Carbon Buildup on Intake Valves (Pre-Dual Injection EA888 Gen 3)
4.2L V8 Carbon Buildup on Intake Valves
Severe Carbon Buildup on Intake Valves
Carbon Buildup on Intake Valves (4.2 V8 FSI and 5.2 V10 FSI)
Severe Carbon Buildup on Intake Valves (2.5T 5-Cylinder)
Turbocharger Oil Strainer Failure (4.0T V8) - CRITICAL
Electronic Water Pump Failure (2.0T)
Intake Valve Carbon Buildup
S65 V8 Rod Bearing Premature Failure
Valve Cover Gasket Oil Leak
G80 S58 Engine Carbon Buildup on Intake Valves
Valve Cover Gasket Oil Leak
S58 Intake Valve Carbon Buildup
S58 Intake Valve Carbon Buildup
S63/S63TU Valve Stem Seal Failure & Oil Consumption
Fuel Injector Failure - 428i/430i/435i/440i F32/F33/F36
N63 Valvetronic Motor Failure - F01/F02 750i/750Li
Electric Water Pump Failure - E85 (N52) & E89 Z4
S63 V8 Rod Bearing Premature Wear & Failure - E70/F85 X5 M
N55 Rod Bearing Premature Wear - F87 M2
S55 High-Pressure Fuel Injector Failure - F82/F83 M4
Electric Water Pump Failure (N52, N20 Engines)
S63 Rod Bearing Failure (X6 M)
B58 Coolant System Failures (xDrive40i)
S85 V10 Rod Bearing Failure (Catastrophic Engine Destruction)
S63/S63TU Ignition Coil Premature Failure
Electric Water Pump Failure (All Engines)
Electric Water Pump Failure (N52, N55, N63 Engines)
Carbon Buildup on Intake Valves (Direct Injection Engines)
S85 V10 Rod Bearing Premature Failure (CATASTROPHIC) - E60 M5
S63TU4 Rod Bearing Wear (M8/M8 Competition)
Electric Water Pump Failure
Direct Fuel Injector Failure (S55)
Rod Bearing Failure (S65 V8) - CRITICAL
S63 Twin-Turbo V8 Rod Bearing Concerns (F06/F12/F13 M6)
V12 Nikasil Cylinder Bore Wear (M70/M73)
Electric Water Pump Failure (All 1 Series E82/E88)
S55 Rod Bearing Premature Wear - F82/F83 M4
Electric Water Pump Failure (All Engines)
Rod Bearing Wear (S54 Engine)
Carbon Buildup on Intake Valves (Direct Injection Engines)
Ignition Coil Pack Failure Causing Misfires and Check Engine Light on M52TU/M54 Engines
Valve Cover Gasket Oil Leaks (M54, N52 Engines)
SMG III Hydraulic Pump Failure - E60 M5
LT4 Supercharged V8 Premature Engine Failure
3.6L V6 Timing Chain Stretch - SRX
Northstar 4.6L V8 Head Bolt/Head Gasket Failure
Northstar 4.6L V8 Head Bolt/Head Gasket Failure
3.6L V6 Timing Chain Stretch and Premature Failure
Northstar 4.6L V8 Head Bolt/Head Gasket Failure
3.6L V6 Timing Chain Stretch (ATS V6 models)
AFM/DOD Lifter Failure - V8 Cylinder Deactivation System
Northstar 4.6L V8 Head Bolt/Head Gasket Failure
5.3L Vortec AFM Active Fuel Management Oil Consumption and Lifter Failure
Injector Wiring Harness Chafing (Duramax)
Cylinder Head Valve Seat Failure and Misfire on 3.5L/3.7L Inline-Five
L99 AFM Lifter Failure and Camshaft Damage on 6.2L Automatic Cars
AFM/DFM Lifter Failure (5.3L/6.2L V8)
HEMI 5.7L MDS Lifter and Camshaft Failure
Pentastar Cylinder Head Failure
Chronic Overheating - Multiple Causes
Cooling System Failures (3.3L/3.8L V6)
Head Gasket Failure (Especially Turbo Models)
3.6L Pentastar Engine Stalling and Head Gasket Failure
Turbocharger Failure (GT/Turbo Models)
3.5L V6 Head Gasket Failure and Overheating
5.7L HEMI MDS Lifter Tick and Camshaft Failure
Timing Belt Tensioner and Water Pump Failure
HEMI MDS Lifter Tick
HEMI MDS Lifter Tick
Pentastar V6 Rocker Arm/Lifter Tick
HEMI Lifter/MDS Tick
Pentastar V6 Rocker Arm/Lifter Tick
Cooling System Failures (3.3L/3.8L V6)
Engine Overheating - Thermostat Housing Debris
Head Gasket Failure
Head Gasket Failure
2.4L Electronic Throttle Body Failure
Gen 1 V10 Head Gasket Failure
Rod Bearing Failure from Oil Starvation (Track Use)
2.3L EcoBoost Head Gasket Failure and Coolant Intrusion
2.0L Direct Injection Carbon Buildup on Intake Valves
1.5L EcoBoost Coolant Intrusion into Cylinders - Engine Block Porosity
Fuel Injector Failure and Rough Running (EcoBlue Diesel)
2.0L EcoBoost Coolant Intrusion - Open-Deck Block Failure
1.6L EcoBoost Engine Overheating and Coolant Loss - Recall 14S11
1.5L EcoBoost 3-Cylinder Coolant Loss and Engine Failure
Triton 2-Valve Spark Plug Blow-Out from Cylinder Head
EcoBoost Coolant Intrusion into Cylinders
Ignition Coil Failure and Misfires (2.5L/1.6L)
4.6L 2-Valve Spark Plug Ejection/Breakage
Ignition Coil Pack Failure
2.0L SPI Head Gasket Failure
5.4L 2-Valve Spark Plug Blow-Out From Cylinder Head
1.5T Earth Dreams Direct Injection Carbon Buildup on Intake Valves
Fuel Injector Debris Causing Misfires and Catalyst Codes
11th Gen 2.0T Direct Injection Carbon Buildup and Idle Vibration
Ignition Coil Failure
Idle and Stalling Problems
Spark Plugs Backing Out - Coil Pack Melting and Engine Damage
Distributor Internal Coil and Igniter Failure (4th Gen)
Timing Belt and Water Pump Neglect Leading to 3.2L V6 Engine Damage
EGR System Clogging (Lean Burn Engine)
Valve Cover Gasket and Spark Plug Tube Seal Oil Leaks Causing Misfires
Theta II Engine Seizure/Failure
Connecting Rod Bearing Failure (Theta II)
Theta II Engine Seizure Due to Connecting Rod Bearing Failure
Theta II Engine Failure / Connecting Rod Bearing Seizure
Excessive Oil Consumption - 2.4L GDI Engine
Nu Engine Bearing Failure and Seizure
Fuel Injector Failure Causing Misfire, Rough Running, and Check Engine Light
Valve Cover Gasket Oil Leaks Onto Spark Plug Wells and Exhaust Manifold
Intake Valve Carbon Buildup (GDI Engines)
Fuel Injector Failure and Engine Stalling
Ignition Coil and Plug Wire Failure Causing Misfire, Hesitation, and Check Engine Light
Timing Belt Neglect Leading to Bent Valves and Sudden No-Start on 1.6L Engines
Ignition Coil Pack Failure Causing Misfire
Apex Seal Failure / Compression Loss
Crankshaft Position Sensor Failure (NB)
Carbon Buildup on Direct Injection Intake Valves
Carbon Buildup on Intake Valves (Skyactiv)
Ignition Coil Failure and Misfires
Skyactiv 2.0L Intake Valve Carbon Buildup
N14/N18 Turbo Engine Timing Chain Catastrophic Failure
Direct Injection Carbon Buildup on Intake Valves
N12/N16 Timing Chain Tensioner Failure
Intake Valve Carbon Buildup from Direct Injection
Carbon Buildup on Intake Valves (Direct Injection) Causing Misfires/Power Loss
VVEL Solenoid Failure (VK56VD Engine)
Excessive Oil Consumption (QR25DE)
2.5L Pre-Catalyst Breakdown Causing Excessive Oil Consumption and Engine Damage
Ignition Coil Failure
Ignition Coil Failure (VQ35DE)
6.7L Cummins Exhaust Brake Actuator and VGT Turbo Issues
HEMI Lifter/Camshaft Failure
5.7L HEMI MDS Lifter Failure
MDS Lifter Failure and Hemi Tick (5.7L)
Head Gasket Failure
EJ253 Head Gasket Failure (External Leak)
EJ25 Head Gasket Failure
EJ25 Head Gasket Failure
Spun Rod Bearing Failure (EJ257)
Head Gasket Issues
FA20 Valve Spring Recall - Engine Stalling Risk
EZ36 Timing Chain Stretch and Guide Wear
EJ257 Piston Ringland Failure
EZ30 3.0L H6 Head Gasket Leak
Valve Spring Recall - Engine Stall Risk
EGR Valve and Intake Manifold Carbon Buildup
Water Pump Leak and Failure (2GR-FE)
1NZ-FXE Head Gasket Failure and EGR Cooler Issues
G16E-GTS Head Gasket Seepage Under Hard Use
1.5L 1NZ-FE Valve Cover Gasket and Oil Filler Cap Leak
Valve Spring Recall (Early Production)
2AZ-FE Excessive Oil Consumption from Piston/Ring Wear
FA20 Valve Spring Recall (Campaign E0G/17V-587)
Excessive Oil Consumption from 1ZZ-FE Piston Ring Wear
2.4L 2AZ-FE Head Gasket and Head Bolt Thread Failure
Intake Manifold Gasket Vacuum Leak Causing Cold-Start Rough Idle and Lean Codes
2AZ-FE Excessive Oil Consumption From Piston/Ring Wear
Direct Injection Carbon Buildup on Intake Valves
Direct Injection Carbon Buildup on Intake Valves
Direct Injection Carbon Buildup on Intake Valves
Intake Valve Carbon Buildup
Ignition Coil Failure
2.5L 5-Cylinder Ignition Coil Pack Failure
EA211 1.5T Engine Ticking and Fuel Injector Noise
EA888 Gen 3 Intake Valve Carbon Buildup (GDI)
Ignition Coil Pack Failure (1.8T/2.0)
2.0L Ignition Coil Pack Failure
Ignition Coil Pack Cracking and Misfires
Direct Injection Carbon Buildup on Intake Valves
FAQ
What does P0304 mean?
P0304 stands for "Cylinder 4 Misfire Detected." Misfires detected specifically in cylinder 4.
What are the most common causes of P0304?
The most common causes of P0304 are: Failed ignition coil, Worn spark plug, Clogged fuel injector, Low compression, Vacuum leak. The specific cause varies by vehicle.
How much does it cost to fix P0304?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0304?
Au7o has documented P0304 across 151 vehicle models from 21 manufacturers: Acura, Audi, BMW, Cadillac, Chevrolet, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Jeep, Kia, Lexus, MINI, Mazda, Nissan, RAM, Subaru, Toyota, Volkswagen.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.