Fuel prices in Kenya are high, and nothing is more frustrating than when your car suddenly begins to consume way more fuel than usual. One week you’re doing 12–14 km/L; the next week you’re shocked to see your tank drain twice as fast.

If your car has suddenly turned into a guzzler, here are the real, scientifically proven, and Kenya-specific reasons behind the spike in fuel consumption — and what you should do.

1. Driving Style Has Changed

Many motorists underestimate how much driving behaviour affects fuel usage.

? Common scenarios in Kenya:

• More time in city traffic (e.g., Waiyaki Way construction, Mombasa Road jam).

• Someone else is driving the car — the askari, teenager, friend, or office driver who accelerates aggressively.

• You started carrying heavier loads, or using a roof rack which increases wind resistance.

Small changes in driving style can increase fuel consumption by 20–40%.

2. Low Tyre Pressure

Under-inflated tyres dramatically increase rolling resistance.

• Even a 5 PSI drop raises fuel consumption.

• A soft tyre can easily cost you 10–20% more fuel.

• Many SUVs have rear-mounted spares — when the spare is flat, it drags the car sideways.

?? Check tyre pressure every 2 weeks (including the spare).

3. Bad or Contaminated Fuel

Yes — kerosene-mixed petrol is still a thing in Kenya.

Situations that increase the risk:

• Fueling at a very cheap or unknown petrol station

• Fuel price hikes (when rogue stations start cutting product)

• Stations with older underground tanks (water contamination)

Bad fuel causes:

• Poor combustion

• Loss of power

• High fuel consumption

• Engine knocking

If consumption changed immediately after fueling, suspect the petrol.

4. Clogged Air Filter

Driving on dusty murram roads (Gitaru, Ruai, Syokimau, Ngong, Kisii, Eldoret outskirts) blocks the air filter faster.

A clogged air filter ? less air ? ECU enriches the fuel mixture ? more fuel burned.

Replace the air filter every:

• 10,000 km (normal use)

• 5,000 km (dusty environments)

5. Faulty Oxygen (O2) Sensor

This is one of the most common causes of sudden poor fuel consumption.

Especially common in:

• Toyota Vitz

• Toyota Premio

• Toyota Fielder

• Toyota Axio

• Toyota Harrier

• Many older Mazdas and Nissans

When the O2 sensor fails:

• The ECU thinks the engine is running lean

• It dumps extra fuel

• Fuel consumption can double overnight

• Sometimes black smoke appears

6. Brake Pads or Shoes Dragging

A stuck brake caliper or a handbrake that doesn’t fully release forces the engine to work harder.

How to check:

After a short drive, carefully touch each rim:

• If one is much hotter, that wheel’s brakes are binding.

This can increase consumption significantly and damage the braking system.

7. Misalignment or Worn Suspension

Kenyan roads + potholes = instant alignment problems.

When alignment is off:

• The car drags sideways

• Rolling resistance increases

• Fuel consumption rises

Bad shocks, worn bushes, or bent suspension arms also worsen the problem.

8. Old, Wrong, or Worn Spark Plugs

Spark plugs ignite the fuel–air mixture. When worn:

• They cause misfires

• The ECU injects more fuel

• Engine efficiency drops

Many Kenyan drivers install 100,000 km iridium plugs then forget about them. Even iridium plugs degrade.

9. Dirty or Leaking Fuel Injectors

Especially common in:

• Toyota 1NR engines (Axio, Fielder, Vitz)

• Direct-injection engines

Dirty injectors lead to:

• Poor spray pattern

• Rich mixtures

• Excessive fuel usage

• Rough idling

A leaking injector is even worse — it drips fuel constantly.

10. Thermostat Stuck Open

If the thermostat is open, the engine never gets to optimal temperature.

The ECU assumes the engine is cold ? keeps mixture rich ? fuel consumption goes up.

Common in older used imports.

11. Air Conditioning Always On

AC increases engine load noticeably, especially:

• In town driving

• When the compressor clutch is faulty and doesn’t disengage

You may lose 1–2 km/L from AC alone.

12. Exhaust Blockage

Rare but possible.

Causes include:

• Collapsed catalytic converter

• Damaged exhaust pipe

• Blocked muffler (sometimes after floodwater exposure)

A blocked exhaust reduces power and worsens fuel economy.

Final Word: Fuel Consumption Never Increases “For No Reason”

If your vehicle suddenly begins consuming much more fuel, you should check:

1. Driver behaviour

2. Tyre pressure

3. Air filter

4. O2 sensor

5. Brakes and alignment

6. Fuel injectors

7. Fuel quality

A simple diagnosis can save you thousands of shillings in wasted fuel.