Whats up with my Car?

Possible air flow fault but if the [MAF] Mass air flow meter is faulty this would usually trigger the engine management light. As you mentioned is has only happened since service was done i would start with checking the black plastic pipe between the air filter housing and the inlet manifold to see if this has been disturbed or damaged and also if the smaller vaccum /oil breather pipes are intact. The petrol smell could be from a breather pipe. hope this helps and good luck.

craig orr
January 2009