P0313: Misfire Detected with Low Fuel

What it means

Misfires are detected while the fuel level is low. The ECM disables further misfire reporting under this condition because intermittent fuel starvation can cause false positives in catalyst-damaging logic.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The engine controller uses crankshaft speed changes to detect misfires and considers fuel-level information when interpreting them. P0313 records a misfire detected while the indicated fuel level is low; fuel starvation can cause uneven combustion, and the controller may limit further misfire reporting under this condition.

Common causes

Most likely first.

1. Fuel level very low
2. Weak fuel pump or pickup
3. Faulty fuel level sensor

Symptoms

• Check engine light on or flashing
• Rough idle and uneven running
• Power loss, hesitation under acceleration
• Increased fuel consumption
• Possible smell of unburned fuel from exhaust

How to diagnose it

1. Check the freeze-frame fuel-level reading and misfire data, then note whether the fault occurred during cornering, braking, or acceleration.
2. Add fuel and see whether the symptoms and code return, since an actually low tank can uncover the pump pickup during vehicle movement.
3. Compare the dashboard fuel gauge with the scan-tool fuel-level reading and check for other fuel-level sensor faults.
4. If misfiring continues with adequate fuel, check fuel pressure and delivery under the conditions specified by the manufacturer.
5. If the fuel level reading is implausible or intermittent, inspect the tank sender circuit and connectors using the vehicle’s service information.

Common fixes

• Refuel if the tank was nearly empty.
• Repair a loose or damaged fuel-level sender connector or wiring.
• Replace a faulty fuel-level sender if testing confirms inaccurate readings.
• Repair or replace a weak fuel pump or restricted pickup if fuel-delivery tests identify the problem.

Can I keep driving?

Refuel promptly and avoid hard acceleration or sharp turns while the tank is very low, as fuel starvation can cause stalling. If the check engine light flashes or the engine runs severely rough after refuelling, stop driving to reduce the risk of catalytic-converter damage.