Poor mpg -low mileage car

I have a 1995 Lexus LS400 done 80000 miles. I only do about 2000 miles per annum. I am getting less mpg than I used to. An item in Sunday Times motoring section advised a reader with similar problem to use a product such as PowerBoost to clean the engine which may be clogged up with carbon etc. Can this really work or should I look for other problems on my car? It is running perfectly (apart from the worsening mpg) and is fully serviced and passes mots on emmissions with no problem.

Asked on 24 February 2011 by AndyCheltenham

Answered by Honest John
Use Shell V-Power petrol exclusively as this will clean up the combustion chambers and the engine needs 99Ron anyway. Not running it on 99Ron is what cased your problem.
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