I had my car - a Skoda Yeti - serviced recently and the fuel efficiency has nose-dived. I took it out on a long run on Friday and instead of getting my normal 48 mpg, I got mid 30s mpg one way and it just hit 40 mpg on the return. Now, the brakes were replaced so I checked them but there doesn't seem to be any sign of rubbing. What else should I check? The car is going back for a timing belt replacement this week anyway so I'll have them check, but if I can solve it myself, I'd like to.