My V reg Renault Clio is using WAY too much petrol... what could be wrong?

[roxanne:t]

So in a week I have had to put in £120 petrol... which I think is way to high, I only do about 30 miles a day?

It went through the m.o.t two weeks ago and passed with no advisory's at all.

The speedo and the temprature gauge doesnt work, could this be the problem?

If not, what else could be the problem?

Any help would be much appreciated

Thanks x