P0313 and P0314: misfire detected with low fuel level

Most misfire codes leave you to work out why. P0313 comes with a hypothesis attached: the engine misfired at a moment when the fuel level was below a threshold, so the ECU flagged the combination rather than the misfire alone.

Code	Meaning
P0313	Misfire detected with low fuel level
P0314	Single cylinder misfire, cylinder not specified

The reason this exists is emissions regulation. A misfire caused by running out of fuel should not condemn the ignition system or count against the misfire monitor in the same way, so it gets its own code.

Related: P0300 random misfire deep dive.

The simple explanation, which is often correct

You drove with the tank nearly empty. Cornering, braking or a hill moved the remaining fuel away from the pump pickup, the pump drew air for a moment, and combustion faltered.

Fill the tank. Clear the code. Drive normally. If it does not return, that was the whole story.

This is one of the few codes where the correct first action is genuinely that simple.

When it is not that simple

If P0313 appears with a tank that was not low, or keeps returning after filling, the “low fuel” part of the code is a red herring and you have a genuine fuel delivery problem that happens to reduce pressure the way low fuel does.

A failing fuel pump

A weak pump maintains pressure at moderate demand and falls short under load. Symptoms concentrate at high load and high speed rather than at low fuel.

P0230 to P0232 fuel pump circuit.

A blocked strainer or filter

The in-tank strainer collects debris over years, and a car habitually run near empty accumulates it faster because sediment sits at the bottom of the tank.

Chronic low-fuel driving is a genuine cause of pump failure, both from the strainer and because the fuel around the pump provides cooling.

Fuel filter replacement symptoms.

A wrong fuel level reading

If the gauge says a quarter tank and the tank is actually nearly empty, you get P0313 with no apparent reason. The sender is the fault, not the fuel system.

Fuel gauge reading wrong and fuel gauge and sender faults.

Contaminated fuel

Water in the tank collects at the bottom and gets picked up first when the level is low. That produces exactly this pattern: fine with a full tank, misfires when low.

Bad fuel quality OBD symptoms.

The data that tells them apart

Log fuel level, fuel rail pressure and misfire counters together.

Pattern	Meaning
Misfires only below 1/8 tank	Genuine low-fuel event
Misfires at any level under load	Pump or supply restriction
Rail pressure drops before the misfire	Delivery fault confirmed
Fuel level reading implausible	Sender fault
Misfires concentrated on one cylinder	Ignore the fuel angle — normal misfire diagnosis

That last row is important. P0313 alongside a specific cylinder code means you have two things: a weak cylinder and a low tank. Diagnose the cylinder.

The habit worth changing

Running consistently below a quarter tank is a slow-motion expense:

• The pump runs hotter, because fuel cools it.
• Sediment gets drawn in more often.
• Condensation forms in the empty volume, adding water over time.
• Any fuel delivery weakness shows up as a driveability fault at the worst moment.

None of this is dramatic in a single tank. Over years it is why pumps fail at 120,000 km on one car and 300,000 on another.

Step by step

1. Fill the tank and clear the code.
2. Drive normally and see whether it returns.
3. If it returns, check whether the fuel level reading is accurate.
4. Log rail pressure under load to test delivery.
5. Check misfire counters by cylinder — a specific cylinder changes the diagnosis entirely.
6. Consider the filter and strainer before the pump.

The practical next step: pair an ELM327 adapter, open the free tier of the app and log fuel level against misfire counters over a week. If the misfires cluster at the bottom of the tank, the code was telling you the truth.