P0300: Random/Multiple Cylinder Misfire Detected
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Short trips at moderate speed are usually tolerable; a flashing check engine light means stop - raw fuel is destroying the catalytic converter.
Symptoms
- Rough or shaking idle, especially at stops
- Hesitation or stumble under acceleration
- Flashing check engine light under load
- Reduced fuel economy and sulfur smell from exhaust
Likely causes, most common first
- Worn spark plugs or ignition coils (most common)
- Vacuum leak leaning out the mixture
- Weak fuel pump or clogged injectors
- Low compression in one or more cylinders (worn engine)
- Faulty crankshaft or camshaft position sensor
Read P0300 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0300 means the engine control module sees misfires spread across several cylinders rather than one. The computer watches tiny variations in crankshaft speed; when combustion fails in random cylinders, this code sets. Because the pattern is random, the cause is usually something shared by all cylinders - ignition wear, a vacuum leak, fuel delivery - rather than a single bad part.
Diagnosis order that saves money: read misfire counters per cylinder, inspect plugs first (age and condition tell a story), then check for vacuum leaks with the engine warm, then fuel pressure. Cylinder-specific codes P0301-P0308 point to one cylinder and narrow the hunt to that cylinder's plug, coil or injector.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0300
“Check engine light on. Codes P0316, P0300, P0301, P0302. Technician confirmed via scope coolant intrusion on cylinder 1 and 2. Technician stated it is known issue with this engine and recommends a new engine for $16,169.92. This has been an ongoing issue for the past two years.”2017 Lincoln MKC · Aug 2026
“vehicle may experience driveability issues, which may result in DTCs P0300 (random misfire detected), P0301 (No. 1 cylinder misfire detected), P0302 (No. 2 cylinder misfire detected), P0303 (No. 3 cylinder misfire detected), P0304 (No. 4 cylinder misfire detected), or P0172 (fuel system too rich) or a whirling noise coming from the engine compartment. POSSIBLE CAUSE Based on certain driving patterns and environmental factors, the DTC's stated above may be set or a whirling noise may occur. Apparently only certain vin numbers were affected, mine is not in the list but im still having the exact same issues.”2017 Honda CR-V · Aug 2026
“Engine started having a rough idle on start up and within a few days the check engine light came on. Took to Lonnie Cobb Ford in Henderson, TN. DTC P0300 and P0302 diagnosed. Coolant leaking on to piston head. Issue involved in lawsuit Miller vs. FordMotor Ecoboost lawsuit. Safety issue due to possible engine lock up or fire. Out of warranty. Quote for $6500 on an $8000 vehicle for an engine defect Ford has been aware of for years.”2016 Ford Edge · Jul 2026
Show 7 more owner reports
“The vehicle in question has the coolant intrusion into cylinders 2 and 3 with rough idle on startup, P0300, P0302, P0303, and white smoke on startup. The vehicle now has 111339 miles on it and the out of pocket cost is more than what the vehicle blue books for in excellent condition. TSB 22-2134 speaks to all the issue and what the repair is. If this is a known issue then I feel this should be a vehicle recall by Ford due to the costly repair.”2017 Ford Fusion · Jul 2026
“I own a 2020 Ford Mustang EcoBoost with approximately 75,000 miles. My vehicle developed a check engine light with diagnostic codes P0300 (random misfire) and P0301 (cylinder 1 misfire). I also began experiencing white smoke from the exhaust during cold starts. An independent repair shop suspects coolant is entering cylinder 1 due to a possible head gasket failure. They have recommended removing the cylinder head to inspect for cracks, check for warping, pressure test the head, inspect the cylinder walls, and replace the head gasket and related components if no further engine damage is found. The vehicle was properly maintained, and these symptoms appeared unexpectedly.”2020 Ford Mustang · Jul 2026
“Back to back error codes P0300 P0108 P1404 P0172 Rough running engine. Very strong smell of fuel at two different times while driving. Vehicle not responding to gas pedal while driving on highway. Repairs at thousands of dollars.”2018 Dodge Durango · Jun 2026
“Coolant Intrusion due to a design flaw leading to coolant entering the combustion chamber causing spark plugs to prematurely fail and in extreme cases cause the engine to hydrolock and bend piston rods. Symptoms are a rough idle, MIL illumination and DTC for Misfires P0300-P0304, Coolant loss and overheating”2018 Ford Escape · Jun 2026
“While driving, the vehicle suddenly displayed “Service ESC” and “Service Traction Control” warnings. Shortly after, the engine stalled and the vehicle became difficult to restart. Vehicle experienced rough running/misfires and loss of power. Diagnostic trouble codes retrieved included P0300, P0106, P3498, P00FF, and U1962. The issue appears intermittent but creates a serious safety concern due to unexpected stalling while driving. Concerned about possible electrical, engine management, or stability control system failure affecting safe operation of the vehicle. No prior warning before incident.”2023 Chevrolet Silverado 1500 · May 2026
“The contact owns a 2018 Ford Escape. The contact stated that while driving the vehicle misfiring, white some, hesitation. The engine light illuminated. antifreeze leaking into the cylinder. The vehicle was taken to an independent mechanic where the diagnostic code P0300 was read and an antifreeze leak into the cylinder and a design flaw in the Eco boost. The manufacturer was not notified of the issue. The approximate mileage was unavailable.”2018 Ford Escape · May 2026
“Engine has developed a miss and has check engine code P0300 random misfires. There are subcodes pending of P0011 and P0016 indicating Crank and Cam misalignment. This has all the classic signs for a failing engine. I am taking this truck in for the GM Picoscope test, the oil was changed to 0w40 mobile one supercar oil approx. 2,800 miles ago when the truck was under Powertrain warranty. I will preform a Blackstone oil test to determine if there is abnormal engine wear. My truck is not in the vin. recall range.”2021 Chevrolet Tahoe · Apr 2026
Cars that report P0300 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0300?
Short trips at moderate speed are usually tolerable; a flashing check engine light means stop - raw fuel is destroying the catalytic converter.
How much does it cost to fix P0300?
Typical US repair costs range from $80 for the simplest fix (spark plugs replacement) to $5,000 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.