Hi. I'm New here and really need some help. I recently bought a fiat punto 1.9 elganza multijet.2006 diesel. It's really thirsty only doing 28mpg I put it on a diagnostic machine which said it needed air mass flow meter and 2 other filters replacing . This has been done but it's still using the same amount of fuel. Has anyone got any ideas of what else might be causing this problem. Thanks