Shouldn't your newer car use less fuel?
The JE is quite a bit heavier, - my previous car was a 1994 J63 2.1td, which weighed in at 1350kg, whereas my JE is a whopping 1720 - thats 30% more weight.
Even if the consumptioncomputer is not very accurate, it definitely shows that it is acceleration that eats the fuel. So, as you say, highway driving is not a big problem, especially since the Espace has a vey slippery body (aerodynamicwise).
In the J63 we averaged (over the year) 7.5-7.6 l/100km - Denmark is a cold country, and my wife (who uses the car most of the time) does only short trips - hardly any highway driving.
I have owned the JE for about 6 months now, - which coincides with a danish winter, so only these last weeks, have I tried starting the car, without the supplemental heater starting too :-/ so I cannot really say where we are, but my guess is about the same as the J63 - which frankly is not quite what I had expected either.
I do however have a wategate solnoid which needs replacement - and it possibly affects the economy somewhat - I will know as soon as I get the new one fitted.
AND, the aircon in the J63 hardly ever worked, - when I finally had it completely renewed and working, I sold the car... silly move, but I had found this nice JE :-)
We bought the JE in Berlin, and drove it back to Denmark - me in the JE, and my wife in the J63, and on that trip, the JE used about 15% less diesel than the J63, so for highway driving, I'm sure you will see better results.
However, I remember the UK motoring press (TopGear) once said that customers complained that especially MPV's were not giving the fuel-economy they promised, and they even pulled out a picture of the the Espace JE to illustrate ...
The modern 1.9dci engine is known for its very good economy, - it is however IMO too small for the Espace, even if it was actually used. The latest (130hp) evolutions of the 1.9dci is however very nice, and it would be my preference, was the JE still produced.
/Lennart