If you were tempted by adverts for a £99 device called the Ctech-3000 that, in the words of its marketing "reduces fuel cost, increases horsepower and reduces exhaust emissions", then think again. The company said that the device had been tested.
The company's blurb went that the "Platinum FuelSaver enhances the fuel burn during the power stroke of the engine ... Save up to 22% on petrol ... Guaranteed to Save You a Minimum of 10% on Fuel Costs".
The Advertising Standards Authority investigated the claims following a complaint, and found that the tests were undertaken on a 1970s Hillman Hunter made under licence in Iran. An expert said that the claimed test results were "not representative". This was because the tests were carried out on one make of car only, and one that wasn't representative of other UK cars, and because the conclusions were based on one set of test results only. Nor was there any evidence of a properly controlled experiment.
In response, the advertisers, Emissions Technology Europe, sent in a paper published by the Society of Automotive Engineers which dealt with the effect on unburned hydrocarbon emissions by plating the top and side surfaces of the piston crowns in an engine with a platinum-rhodium coating.
The ASA reckoned that the paper was not research carried out on the advertised product and "understood that it did not support the claim to enhance the fuel burn during the power stroke of the engine. The ASA told the company "to remove the claim until they held comprehensive and carefully controlled test results prepared by an independent laboratory carried out on the advertised product."
Moral: if it sounds too good to be true, it almost always is.