Righto, just something I noticed when I'm driving on nearly any road (Except perfectly flat)
Even the slightest upward grade can have a massive effect on my FE. Going 65 down the highway, I'll get anywhere from 45 to 25 mpg, depending upon the slope. (And we're not talking about massive changes. I live in Northern Indiana for pete's sake. The slopes are barely there at all...)
Is it due to the fact that I have a heavy (3500lb), but aerodynamic(.35 drag coefficient) car that my biggest effect is caused by slope? (From 55 to 65, I see maybe a 2-3 mpg loss, but on a slight uphill, I can get a 10mpg loss)
My 4Runner weighs in at about 3600lbs and I see the same problem going up grades. I try to let it bleed off speed when going up hill by taking it off cruse and just hold a steady pedal. Also I try and stay behind something big if I can.
If it were not for having to cross a 200' high bridge every day my FE average would be significantly higher. Take a look at the Bridge I'm talking about, its rather interesting. http://bridgehunter.com/la/st-charles/luling/
Bottom line is it takes a lot of energy to go up a hill.
Do you see your scangauge numbers jump up and down even on level ground? Mine does this and I'm trying to figure out the real reason, I suspect its my thermostatic fan clutch activating.
Yes, it's normal. What are you worried about, anyway? Mid-20 MPG numbers aren't terrible for a TurboCoupe. A few of the Merkur guys are getting 28 or so with the 2.3T, but our cars are a bit more aerodynamic than ye olde 'birds.