siena missing and heavy on fuel

[mieliemonster]

Hi everyone. I drive a fiat siena 1.2 el. It worked fine but the other day it started missing and fuel consumption is very heavy. Also a heavy fuel smell. What can the problem be? It is going in for a diagnostic check tomorow but I would like o know what the problem could be. Any help would be much appreciated. Thankyou

 

[Peter Pick-Up]

Bad O2 sensor...??