If you’ve noticed your car using more fuel than usual, it may be suffering from poor fuel efficiency. This can be caused by engine, fuel system, tyre, or sensor issues. Reduced gas mileage not only costs you more at the pump but may also signal underlying mechanical problems that need attention.

What does it mean if your car is getting worse gas mileage?

Poor fuel economy means the engine is burning more fuel than necessary to travel the same distance. This can result from improper air-fuel mixture, inefficient combustion, extra rolling resistance, or faulty sensors that disrupt engine performance.

Common causes of poor gas mileage

• Dirty or clogged air filter
• Worn spark plugs or ignition issues
• Underinflated or misaligned tyres
• Dirty fuel injectors
• Faulty oxygen sensor or mass airflow sensor
• Dragging brakes or worn wheel bearings
• Excessive idling or aggressive driving habits

Why do you need to fix this problem quickly?

Lower fuel economy increases your running costs and may indicate that your engine is under strain. Ignoring the problem can lead to further mechanical wear, higher emissions, and in some cases, engine damage.

How do you know when to get it checked?

Signs include:

• More frequent trips to the petrol station
• Check Engine Light illuminated
• Loss of engine power or sluggish acceleration
• Unusual exhaust smoke or fuel smell
• Noticeable drop in kilometres per litre compared to normal

What happens during an assessment?

A mechanic will:

1. Check tyre condition and pressure
2. Inspect air filter, fuel injectors, and spark plugs
3. Scan the ECU for fault codes from sensors (oxygen, MAF, etc.)
4. Inspect brakes and wheel bearings for drag
5. Test fuel pressure and engine performance
6. Advise on repairs or replacements to restore efficiency

How much does it cost to fix?

Costs vary depending on the cause. Simple fixes like air filter or spark plug replacement may cost $100–$250. Sensor replacement or injector servicing can range from $250–$600. More complex fuel system or engine repairs may cost $800–$1,500+.

Is it unsafe to drive with poor gas mileage?

Not immediately unsafe, but poor fuel economy indicates your engine isn’t running efficiently. Over time, this can increase emissions, reduce reliability, and lead to breakdowns. Getting it checked will save you money and protect your vehicle.