[mdbrjb]

Approximately 4 mpg difference.

From Toyota's website (2007):

2.7 Acc Cab Prerunner = 23/28 (5 speed manual)
4.0 ACC Cab Prerunner = 19/22 (6 speed manual)

Looks like city is 4 mpg difference and highway is 6 mpg.

Now of course how you drive can make a big difference. I've never seen 28 highway with my 05 2.7 reg cab prerunner cause I'm rarely under 75 mph.

City I average around 22 or 23. Highway around 24 or 25. Pulling my 2000 lb pop up trailer at 70 around 20 mpg. There are probably a lot of 4.0 owners doing just as good. There might be some 2.7 drivers getting better...

Also, I live in the foothills. If I lived in Ohio I'll bet I could pick up another mile or two per gallon.

Like they say: "your mileage may vary."