I don't own a 4th, 3rd, 1st, or GTO for that matter.
As far as the 5th gen is concerned...They were looking at 30+ mpg highway, which is entirely feasable, and welcome! They can do that through AFM, active fuel management; VVT, variable valve timing; direct injection; and very intelligent gearing: two overdrive gears...nice
My 2nd gen, if we're looking for 'afternoon' tidbits, is rated at 16 mpg...and since everything is listed as hwy (because it looks better) thats what I'm assuming it is. But give is a break, we're talkin' 350ci, with a 4 barrel carbeurator, what do you want?!?!
And does the GTO offer AFM? I guess what I'm asking is what engine does it use?
NOTE: I gave the meanings to the abbreviations above merely for those who might not have known...NO SPECIFIC person, just as a courtesy
NOTE 2: a word for a moment on direct injection, and VVT. Direct Injection spritzes Gasoline (or whatever fuel) directly into the Cyllinder, whixh actually cools the air a little, compressing it - albeit minor compression. And VVT can alter Valve timing on-the-fly, which gives an increase in both performance and Fuel economy. It also eliminates the need for a conventional EGR (exaust gas return) system. Together, this is a powerful tool for creating power: i.e. the 300hp V6 that Caddy is using utilizes these advancements together, which, IMO, is the whole reason a V6 of this size can reach those numbers.