I have a 96 Z-T56, Heads/Cam(ZZ409), full exhaust, CAI, with 51K on the clock.

I drove to Iowa last summer and I got 29.6 MPG on the drive down there averaging about 75mph. Normally I get about 27mpg on the highway, and about 15-17 mpg in the city.

 

About 240 miles to the tank combined city/highway. New engine (maybe 5k).

 

seems to depend on the gas and obviously the city:highway ratio. On shell v-power gas and at least 75% highway i hit 20-21mpg. On most others with the same ratio i get 18-19. Its an m6 by the way

 

With everything in my sig. I was getting 30mpg from Gulfport, MS to Shreveport, LA all highway. I get about 15-16 in city.

 

so i guess i was getting about what it should get. 17-18 city/hwy driving. thats good to know

 

138k on the clock
Headers, Borla, Intake, 160stat, stock tune, !AIR

12.2 and 11.6 last two tanks.

 

I can't seems to get more than 20MPG on mostly highway and I have a 6-speed! Just replaced plugs and wires and cleaned my MAF (which everyone should do by the way) so maybe I will get better next time around. (Like 3 days LOL)

 

I average 17-19 mpg in the city and 25-29 mpg on the highway. The highest I have seen was 31 mpg, but that was strictly highway driving going from one gas station to the next. The lowest I have seen is 15 mpg and that was beating the living snot out of the car. I drive my car aggressive and have 50/50 city-highway driving and average 21 mpg/week. This is on my 1996 M6 with mods below and 85,000 miles.

Jeff

 

Just did 270miles to my last tank all city driving. Best I ever got was 34mpg with the cruise set on 60mph and drove like an old lady. I got 27mpg all hwy last year doing 90mph

 

184,000 miles
17 mpg city
21-22 mpg highway

I have a heavy foot sometimes, most I got was 290 on a tank with a city/highway mix. Also... I hate you t-56 guys!

 

About 17 all city. You really need to go WOT every once in awhile though, as you guys probably know

EDIT: 123,000k 93 Trans Am

 

I normally average 22-23MPG combined hwy/city driving rarely below 80-90mph on the highway and have a M6.
If I do 90% hwy driving it is around 26mpg. I normally have about 30% city and 70% hwy driving, thus the 23mpg avg.
If 90% city driving it is around 17mpg, provided I don't ride the loud pedal too much.
I have gotten as high as 29.9 mpg on the highway on a 200+ mile trip at 80+mph. Once I drove the same trip at between 70-75mph and got 32mpg.
Did I mention I have 265,000 miles on my original engine ?
I attribute the good mileage and longevity to relying exclusively on Redline 20w50, even in the winter, changed every 12,000 miles.

 

I get 26 on the highway. Not sure about city. 3.42 and 17" wheels.

 

i get 15-16mpg around town...i average 21-22mpg on the highway with a little city mixed in

 

17 to 19 city

24 to 26 strictly highway

light mods: chip, K & N air filter, underdrive, hi flo cat with 3" exhaust, heads shaved due to blown head gasket, >103k (miles not km)