Found 15th Jul
my gf as a mark 2 1.6 petrol focus. it's mpg is shocking. 25mpg. she does very short trips under 2 miles. apart from changing car is there anything else than can be done to improve mpg. I've changed oil, filter, plugs etc. one thing I particularly want advice on is I'm currently using a 5w30 oil. would swapping to 0w30 help fuel economy or be so bad for engine? thanks in advance.