Consumers misled over mpg claims, says Which?

Car manufacturers have been accused of giving motorists false fuel consumption figures in the UK.

A team from Which?, the Consumers’ Association magazine, found all but three of 200 new cars tested fell short of the makers’ miles-per-gallon (mpg) claims.

Under the official test rules the figures can be calculated when lights and air conditioning are turned off, tyres are highly inflated, and a car is switched to eco mode, which is intended to improve fuel efficiency.

Consequently, the calculations do not apply to normal use, which would include, for example, short journeys and motorway driving, says Which?

The most vivid example listed is Mitsubishi’s claim for its plug-in hybrid Outlander PHEV, which the magazine says is 120% overstated and can lead to £459 in unexpected extra fuel costs for 10,000 miles a year. Overstatements on average are put at 13%.

Another example is the Jeep Grand Cherokee. The magazine says the mpg claim is 55% overstated, so that motorists would pay £854 a year more than expected. The figure is particularly high as fuel consumption is high anyway.

The magazine says an improved test being introduced by the European Commission in 2017 is more realistic and would eliminate “fantasy mpg figures”, but the car industry wants it postponed to 2020.

Mitsubishi, branded the worst offender, agrees the present test, created in the 1970s, is outdated but points out that companies are legally bound to apply it and publish the results.

The Outlander PHEV carries an official 148mpg claim. Mitsubishi says: “Longer journeys may reduce this figure but the Outlander PHEV will still return impressive economy. Even the 67.3mpg suggested by Which? is good for a large 4x4 SUV.”

Mitsubishi says motoring magazines reported its “refreshing honesty” in presenting mpg expectations for the model.