Random or Multiple Cylinder Misfire Detected
What it means
The engine computer has detected incomplete combustion in more than one cylinder, with no fixed pattern. This usually points to something shared by all cylinders, such as low fuel pressure, a vacuum leak or worn spark plugs, rather than one faulty part in a single cylinder.
Related lights
Dashboard lights that may come on with this code.
Symptoms5
- Noticeable engine shaking, especially at idle or under acceleration.
- Loss of power and hesitation when pressing the accelerator.
- Check engine light on, possibly flashing during severe misfires.
- Higher fuel consumption.
- Smell of unburned fuel from the exhaust.
Possible causes7
- Worn spark plugs across all cylinders.
- Vacuum leak from cracked hoses or a leaking intake manifold gasket.
- Low fuel pressure from a weak pump or clogged fuel filter.
- Dirty injectors or poor-quality fuel.
- One or more weak ignition coils.
- Incorrect readings from the mass airflow (MAF) sensor.
- Low compression or incorrect engine timing (less common).
How to diagnose6
- Read all stored codes; lean codes such as P0171 or P0174 point toward a vacuum leak or fuel delivery problem.
- Watch the per-cylinder misfire counters on a scan tool to see which cylinders are most affected.
- Inspect the spark plugs for wear, color and gap.
- Listen for hissing and inspect vacuum hoses, or have a smoke test done.
- Measure fuel pressure and compare it with the manufacturer specification.
- Have a compression test done if the misfire remains after the checks above.
How to fix6
- Replace the spark plugs if they are due or show wear.
- Swap ignition coils between cylinders and replace any coil the misfire follows.
- Replace the leaking vacuum hose or gasket.
- Clean the MAF sensor with a dedicated cleaner.
- Clean or replace the injectors, and replace the fuel filter or pump if pressure is low.
- Clear the codes, then road test and confirm the code does not return.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
In the Saudi market: SAR 150–2,500 (≈ USD 40–667)
Our prices come from the Saudi market, converted at a fixed rate (SAR 3.75 per USD). Prices in your country may differ a lot, so we show the cost level.
The cost is low when spark plugs or a vacuum hose are to blame, and rises when the fuel pump, injectors or internal engine repairs are involved.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
Can I drive with this code?
Only a short distance and gently. If the check engine light is flashing, stop driving, because unburned fuel overheats the catalytic converter and can destroy it.
Why doesn't the computer name the faulty cylinder?
Because the misfire moves between cylinders with no fixed pattern, which itself suggests a shared cause affecting the whole engine.
Will new spark plugs fix it?
Sometimes, if the old ones are worn. If the code returns, look for a vacuum leak or low fuel pressure.
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