P0300 High Powertrain

Random/Multiple Cylinder Misfire Detected

Common Causes

Worn or fouled spark plugs
Failed ignition coil(s)
Dirty or failed mass airflow sensor
Vacuum leak causing lean misfire
Low fuel pressure
Failed fuel injector(s)
Low compression

Common Symptoms

Rough Idle Engine Stalling Engine Hesitation on Acceleration Engine Misfires Black Exhaust Smoke Poor Fuel Economy

Related Videos

5:40
EricTheCarGuy Explains Check Engine Codes - P0300 Random Misfire Detec...
TRQ 488K views
2:56
How to Fix a Random Engine Misfire in Your Car (Code P0300)
Scotty Kilmer 3,546K views
4:30
P0300 Explained - Random/Multiple Cylinder Misfire Detected (Simple Fi...
FIXD 863K views

Common Repairs

#1 Replace Spark Plugs
1–2 hours $50 – $150 Easy

Worn or fouled spark plugs are the most common cause of rough idle and misfires on high-mileage vehicles.

Parts Needed

Spark Plugs (set of 8) Ignition Coil Pack (optional)
#2 Clean or Replace Mass Airflow Sensor
15–30 min $8 – $120 Very Easy

A dirty MAF sensor sends inaccurate air readings, causing the ECU to run a rich or lean mixture causing rough idle.

Parts Needed

Mass Airflow Sensor (optional)
#3 Clean Throttle Body
20–30 min $5 – $15 Very Easy

Carbon buildup on the throttle plate disrupts airflow at idle. Cleaning often resolves rough idle without parts.

Was this information helpful?

Quick Info

Code P0300
System Powertrain
Severity High
Repairs 3 known

Disclaimer

This information is for diagnostic guidance only. Always verify repairs with a qualified technician before performing safety-critical work.

Track your repair and verify the fix with the FaultFix app

Connect an OBD2 scanner · rescan after the repair · earn a verified fix credit

App Store Google Play