P0313 Misfire Detected with Low Fuel Level

P0313 is an OBD-II diagnostic trouble code indicating that the engine control module (ECM/PCM) has detected a misfire while the fuel level is low.

The important point is that P0313 does not simply mean “the fuel tank is empty.” The ECM has detected combustion irregularity and, at the same time, determined that the vehicle's fuel level is low enough that fuel starvation or unstable fuel delivery may be a possible reason for the misfire.

This code is therefore different from a normal cylinder-specific misfire code such as P0301 or P0302.

P0313 does not necessarily identify which cylinder is misfiring. Instead, it connects the misfire event with a low-fuel operating condition.

Why Can Low Fuel Cause a Misfire?

The engine needs a continuous and stable supply of fuel.

When the fuel level becomes very low, the fuel pump can have difficulty maintaining a consistent fuel supply, particularly under certain driving conditions.

This becomes more likely when the vehicle is:

• Accelerating hard

• Climbing a hill

• Cornering aggressively

• Braking heavily

• Driving at high engine load

• Operating with very little fuel remaining

Fuel inside the tank also acts as a reservoir around the fuel pump pickup.

When the tank is nearly empty, fuel can move away from the pickup during acceleration or cornering.

The pump may then temporarily draw in air or receive insufficient fuel.

The result can be:

Fuel level very low → fuel moves away from pickup → fuel pressure or fuel flow drops → injector delivery becomes insufficient → mixture becomes too lean → combustion becomes unstable → misfire is detected.

P0313 Does Not Prove the Fuel Pump Is Bad

This is an important distinction.

A low fuel level can cause a genuine misfire even when the fuel pump is completely healthy.

For example, a vehicle with a properly functioning fuel system may still misfire if it is driven aggressively with only a very small amount of fuel in the tank.

On the other hand, if P0313 repeatedly appears even when there is plenty of fuel in the tank, the fuel system deserves much closer attention.

Possible problems include:

• Weak fuel pump

• Restricted fuel filter

• Restricted fuel pickup

• Fuel pump strainer problem

• Low fuel pressure

• Fuel pressure regulator problem

• Fuel pump electrical supply problem

• Wiring or ground problem

• Fuel tank contamination

Therefore, the fuel level is an important clue, not automatically the failed component.

What Does the ECM Actually Detect?

The ECM does not directly “see” a misfire in the combustion chamber.

It generally detects misfire by monitoring tiny changes in crankshaft rotational speed.

When a cylinder produces normal combustion, it contributes torque to the crankshaft.

When combustion is weak or absent, that expected acceleration does not occur.

The crankshaft therefore slows slightly more than expected.

The ECM analyzes these changes and can determine that a misfire has occurred.

If the vehicle also reports a low fuel level, the ECM can associate the misfire with a possible fuel-supply problem and set P0313.

Common Causes of P0313

Extremely low fuel level

This is the simplest and most direct possibility.

If the code appeared while the fuel tank was nearly empty and disappeared after refueling, fuel starvation may have been the actual cause.

Weak fuel pump

A worn pump may maintain adequate pressure under light load but fail to provide sufficient volume when demand increases.

This can become especially obvious when the fuel level is low.

Restricted fuel pickup or strainer

A partially blocked pickup can limit fuel flow to the pump.

Fuel filter restriction

A restricted filter can cause pressure or volume problems, particularly under high load.

The exact fuel filter arrangement varies by vehicle.

Fuel tank contamination

Water, dirt, rust particles or other contamination can interfere with fuel pickup and delivery.

Fuel pressure regulator problem

A faulty regulator can cause fuel pressure to be too low or unstable.

Fuel pump electrical problem

The pump may not be receiving the voltage or current it needs because of:

• Corroded connectors

• Damaged wiring

• Poor ground

• Failing relay

• Voltage drop

Fuel injector problem

A restricted or malfunctioning injector can cause a lean condition and misfire, although a low fuel level may be coincidental.

Ignition problem

A weak ignition coil, worn spark plug or damaged ignition component can produce a genuine misfire. The low fuel level does not necessarily mean the fuel system is responsible.

Air/fuel mixture problem

Vacuum leaks, intake leaks, incorrect sensor information or other mixture problems can also produce misfires.

Fuel level sensor problem

If the fuel gauge or fuel-level sensor reports an incorrectly low fuel level, P0313 may be misleading.

The engine could be receiving sufficient fuel while the ECM believes the tank is nearly empty.

The Fuel Level Sensor Matters

The fuel-level information used by the ECM may come from a fuel level sensor inside the tank or through another module/networked system.

If the sensor is inaccurate, the ECM could believe the vehicle has very little fuel when the tank actually contains a substantial amount.

For example:

Actual fuel level: 40%

but

Reported fuel level: very low

If a misfire occurs at the same time, the ECM may set P0313 even though fuel starvation was not the real cause.

This is why the fuel level reported by the scan tool should be compared with the actual amount of fuel in the tank when diagnosing a persistent P0313.

When P0313 Appears Only When the Tank Is Nearly Empty

This pattern is particularly useful.

Suppose the vehicle operates normally when the tank is above half full.

As the fuel level becomes very low, the engine begins to hesitate during hard acceleration and P0313 appears.

That strongly supports investigating:

• Fuel pump

• Fuel pickup

• Pump strainer

• Fuel pressure

• Fuel volume

• Fuel movement inside the tank

A weak fuel pump can become much more noticeable under these conditions.

However, the code should still be confirmed with fuel-pressure and fuel-delivery testing rather than assuming the pump has failed.

When P0313 Appears With Plenty of Fuel

This situation changes the diagnosis.

If the tank contains plenty of fuel and P0313 continues to occur, investigate whether:

• The fuel level sensor is reporting incorrectly

• Fuel pressure is actually dropping

• The fuel pump is weak

• The fuel filter is restricted

• There is an ignition-related misfire

• An injector is malfunctioning

• The engine has an air/fuel mixture problem

• Another sensor is providing incorrect information

In this situation, simply filling the tank should not be considered a permanent repair.

Symptoms You May Notice

P0313 can produce symptoms ranging from almost unnoticeable to severe.

Possible symptoms include:

• Check Engine Light

• Engine hesitation

• Rough idle

• Engine shaking

• Poor acceleration

• Loss of power

• Surging

• Extended cranking

• Stalling

• Engine stumbling during cornering

• Engine stumbling during hard acceleration

• Reduced fuel economy

If the fuel supply becomes severely interrupted, the engine may stall completely.

Why Does the Problem Sometimes Happen During Cornering?

This is a classic fuel-starvation scenario.

When the tank is nearly empty, fuel can move toward one side of the tank during a turn.

If the fuel pump pickup is temporarily exposed or surrounded by insufficient fuel, the pump may not receive a stable supply.

The engine can then experience a brief fuel-pressure or fuel-volume drop.

This may last only a moment.

If the ECM detects the resulting combustion disturbance, it can record a misfire.

This is one reason the driving conditions at the moment P0313 was set are so important.

Why Can Hard Acceleration Trigger P0313?

Fuel demand increases significantly when the driver requests high engine torque.

At the same time, acceleration causes fuel to move within the tank.

If the tank is nearly empty and the fuel system is marginal, these two conditions occur simultaneously:

Higher fuel demand + unstable fuel pickup

The fuel pump may be unable to maintain the required fuel pressure or volume.

The mixture can become too lean, resulting in a misfire.

This is why a vehicle may drive normally at steady speed but stumble during aggressive acceleration when the tank is nearly empty.

How P0313 Should Be Diagnosed

The first step is to determine whether the misfire really occurred because of low fuel availability.

1. Check the actual fuel level

Do not rely exclusively on the dashboard gauge.

Confirm how much fuel is physically in the tank.

If P0313 occurred with only a few liters remaining, that is significant information.

2. Check freeze-frame data

Look at:

• Engine RPM

• Engine load

• Vehicle speed

• Coolant temperature

• Fuel level

• Throttle position

• Fuel trims

• Other available parameters

The operating conditions at the moment the code was recorded can reveal whether the problem occurred during acceleration, high load or another condition.

3. Scan for additional misfire codes

Look for:

• P0300

• P0301

• P0302

• P0303

• P0304

• Other cylinder-specific misfire codes

If P0313 appears together with a specific cylinder misfire, the diagnosis should not automatically be limited to fuel starvation.

For example, P0313 plus P0302 could indicate a cylinder 2 misfire that happened while the tank was low, but the actual cause could still be ignition, injection, compression or fuel delivery.

Check Fuel Pressure Under Load

A fuel-pressure test at idle is not always enough.

A weak pump may produce acceptable pressure while the engine is lightly loaded but fail when fuel demand rises.

Therefore, if fuel delivery is suspected, pressure should be evaluated under the conditions where the problem occurs, using the manufacturer's specifications and appropriate test equipment.

Depending on the vehicle, useful measurements may include:

• Static fuel pressure

• Running fuel pressure

• Pressure under acceleration

• Pressure during high load

• Pressure after shutdown

• Fuel volume/flow

A pressure number that looks normal at idle does not automatically prove that fuel delivery is adequate under load.

Fuel Pressure and Fuel Volume Are Not the Same

This distinction is important when diagnosing P0313.

A fuel system can sometimes show acceptable pressure while still having insufficient delivery volume under certain conditions.

For example, a restriction or weak pump may allow the system to maintain pressure at low demand but fail to deliver enough fuel when the injectors require substantially more fuel.

Therefore, depending on the vehicle, fuel volume testing can be just as important as pressure testing.

Check the Fuel Pump Electrical Supply

If fuel pressure or volume is low, do not automatically replace the pump.

Measure the electrical supply at the pump under operating conditions.

Check for:

• Voltage drop

• Poor ground

• Corroded terminals

• Damaged wiring

• Weak relay

• Connector heating

• Poor electrical connections

A pump that receives insufficient voltage may perform poorly even though the pump itself is mechanically capable of producing the required pressure.

Check the Fuel Filter and Pickup

If the pump is working but delivery is restricted, inspect the components between the fuel tank and engine.

Depending on the design, this may include:

• Fuel filter

• Pump strainer

• Pickup assembly

• Fuel lines

• Tank components

A partially blocked filter may become particularly noticeable during high fuel demand.

Check the Ignition System Too

P0313 is a misfire code, so ignition should not be ignored.

A weak spark can cause the engine to misfire regardless of fuel level.

Check components such as:

• Spark plugs

• Ignition coils

• Coil boots

• Wiring

• Ignition power supply

A useful clue is whether the misfire follows a particular cylinder.

If a specific cylinder repeatedly produces a misfire code even with a full tank, ignition or injector diagnosis becomes more important.

Check Fuel Trims

Fuel-trim data can provide useful supporting evidence.

If the engine is experiencing a lean condition, positive fuel trims may increase because the ECM is attempting to compensate by adding fuel.

However, fuel trims must be interpreted according to operating conditions.

A positive fuel trim does not automatically prove a weak fuel pump.

Vacuum leaks, unmetered air, exhaust leaks affecting oxygen-sensor readings, injector problems and other conditions can also influence fuel trims.

Could P0313 Be Caused by Bad Gasoline?

Poor-quality or contaminated fuel can contribute to misfire.

Water contamination, incorrect fuel or significant contamination can interfere with combustion and fuel delivery.

However, simply blaming “bad gasoline” whenever P0313 appears is not a reliable diagnosis.

If the code appeared immediately after refueling, fuel quality may deserve attention, but fuel pressure, ignition and other relevant systems should still be evaluated.

Could P0313 Be Caused by a Bad Fuel Level Sensor?

Yes.

If the fuel-level sensor reports a low level incorrectly, it can contribute to the conditions under which P0313 is set.

This becomes particularly suspicious when:

• The dashboard fuel gauge behaves incorrectly

• The scan tool shows an implausible fuel level

• The tank is known to contain plenty of fuel

• Fuel starvation symptoms are absent

The fuel-level signal should be compared with the actual fuel quantity.

P0313 vs. P0300

These codes both involve misfire, but they provide different information.

P0300 – Random/Multiple Cylinder Misfire Detected

The ECM has detected misfire affecting multiple cylinders or a random pattern.

P0313 – Misfire Detected with Low Fuel Level

The ECM has detected a misfire while the fuel level is low enough to make fuel starvation a potential factor.

P0313 therefore gives an important contextual clue that P0300 does not.

P0313 vs. P0312

P0312 is a different type of misfire code and identifies a misfire on cylinder 12.

P0313, by contrast, relates the detected misfire to a low fuel-level condition.

The number in these two codes should not be confused.

Can P0313 Damage the Catalytic Converter?

A severe or persistent misfire can.

When a cylinder fails to burn the air/fuel mixture correctly, unburned fuel can enter the exhaust system.

The catalytic converter is not designed to continuously process large quantities of unburned fuel.

Excessive temperature can result, potentially damaging the catalyst.

If the Check Engine Light is flashing and the engine is visibly misfiring or shaking, continued driving should be minimized.

Should You Replace the Fuel Pump?

Not based on P0313 alone.

A fuel pump replacement becomes reasonable when testing demonstrates that the pump cannot maintain the required pressure or volume under the relevant conditions.

If the pump passes its tests, look elsewhere.

Likewise, if the problem occurs only when the tank is nearly empty, inspect the pickup, tank design and fuel delivery system before condemning the pump.

A Practical Diagnostic Sequence

A sensible workshop approach is:

Confirm fuel level → scan all codes → inspect freeze-frame data → determine whether misfire is cylinder-specific → monitor fuel pressure → test fuel volume if required → check pump voltage and ground → inspect filter/pickup → check ignition and injectors → evaluate fuel trims → verify fuel-level sensor accuracy.

The exact order can change depending on the vehicle and symptoms.

Final Thoughts on P0313

P0313 – Misfire Detected with Low Fuel Level is a useful diagnostic clue because it connects a detected engine misfire with a condition in which fuel starvation or unstable fuel delivery may be possible.

If the vehicle was almost out of fuel and the engine stumbled during acceleration or cornering, the explanation may be relatively simple: the fuel pump temporarily lost a stable supply of fuel.

But if P0313 continues to appear with a substantial amount of fuel in the tank, the diagnosis needs to go further.

Fuel pressure, fuel volume, pump electrical supply, fuel pickup, filter restriction, injectors, ignition components and the accuracy of the fuel-level signal should all be considered.

The most important principle is this:

P0313 does not automatically mean “bad fuel pump.” It means the ECM detected a misfire under low-fuel conditions, and the fuel system should be investigated as a potential cause rather than assumed to be the cause.