Took my BA Fairmont that I bought from a Ford dealership back the other day and they updated the the programing of ECU. Now I have filled it up with a tank of fuel and it seems to be a bit more thirsty than it previously was. It has roughly done 190km's from half a tank. I have not been revving it hard either.

Will it need a few more tanks to settle itself down or will this be its new range? When i filled it up, it said 508km's till empty. Now after doing 190km's, it says 240km's till empty. Shouldn't it be saying 318km's till empty from the amount of km's I have done? And if I have done 190km's in half a tank, the range when I filled up the car should have been more like 380km's, which is quite poor, even my EB did more than that.

Hope I haven't confused you guys, that was they best way I could put it across

The tune may have made it more rich.
But also take into concideration heat, humidity, head wind and fuel quality varies.

True, actually now I think of it I have been using a different type of fuel. I usually use Shell but have been using Caltex on the last fill cause I won a $200 fuel voucher. But still I think if you drive lightly, you should be able to get 500km's out of a tank of fuel in a BA.