Hyundai Repair: V.Poor mileage to full tank, hyundai accent 2001, poor fuel economy

Question
Im in the uk, own a hyundai accent 2001 model with a 1.3 engine.....recently ive noticed the fuel consumption go through the roof, a full tank (40ltrs approx) is only going to get me 150-200miles compared to the 300+ when i bought it 5 months ago and I have no idea why....the cars done 69000miles so requires the timing belt replaced is this the cause?

Answer
The timing belt is almost certainly not the issue.  The only way I can surmise that the timing belt could be the cause is if the belt were in such poor condition that the camshaft is no longer correctly timed.

Check the following:
-- Is your check engine lamp on?  If so, the cause of the lamp may well be the cause of your poor fuel economy.
-- Does the vehicle have the same amount of power it did before?
-- If an automatic, does the transmission shift into all forward gears?