Consuming a lot of gasoline vs MPG

[MetroMPG]

Effect unless there's something wrong with the car, then driving environment & driving style have the biggest effect.

EG: if (A) it's an automatic transmission, and (B) you're running air conditioning full-time, and (C) driving short trips in urban conditions, with (D) aggressive driving techniques.... that's a worst case scenario.

Track your next couple of fill-ups and report back.

Track distance travelled & amount of fuel to completely re-fill the tank each time.