First week I had my car I got like 9 and I was absolutley driving the hell out of it. There is no reason it should be that bad.

 

i get 18-20 on my stock 05...i would have thought id get more.

 

i get no less than 15 and that is driving the hell out of my car i mean on it all the time, my dads 390bb f-250 gets 10, something is wrong you should be getting more like 15.8

 

22.3 mpg outta my 94 cobra... mostly stock... bbk o/r x-pipe....

im guessing you have a few things that just "aren't right"

check your fuel filter, air filter, check your exhaust (if you still have cats)
plugs, wires, TIMING!!!!!!

 

i came up with 5.8 buy dividng my # of gallons and mileage . 12 gallons and 80 miles per tank. Yes i had the carb tuned after i installed it, i also changed all the filters. I tried different driving styles and it nmade no difference, i even took the jets out of the stock carb., and that too made no difference.

I sold the car the day i started thi thread. But am still curious as to y it was doing that.

 

5.8mpg?

i couldnt get that if i tried with running on 4 cylinders




btw: Getting consistant 21-23 with a bunch of mods and 3.08s