My 92 shortbox 5-speed got great mileage, I bought it new and can remember 18-20 around town and 25 on the highway. 92 was the best year for the V6 though, and I am sure the 5-speed helped. Still wish I never sold that one...
The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.
Still wish I never sold that one... 
