Thread: whats peoples average mpg on 3.4 setup?

so with gas prices $3.50 + a gallon for supreme iv come to realize my car has issues. i get about 150-180miles on a 3/4 tank now i have a friend who used to have the same setup i do sept ran a 3.25 and got 300+ on a full tank. i was just wondering what other people are getting? my mods are headers,3.4,ported blower, custome tune. 4" intake, egr and rear 02 are tuned out. i was getting a p0440 code but i belive i fixed it with a new gas cap. is anyone can help enlighten me why my mpg is so bad id like to hear it! oh and i have been driving like a old lady since iv been putting 100+ a week in gas. so its not my driving.

Has your car been well maintained? Seafoamed? Injectors cleaned? Plugs changed?

yup new plugs,wires,fuel pump and filter within the last 3k miles same as oil. i seamfoad about the same time aswell. just put yet anether thing of lucas injector cleaner in. oh and i run 255 16's if that matters anyway.

both kinda, i really only drive to work and home cuz of this issue, and its 25 miles each way. about 15 is freeway each way.

I got 30 pure highway, 20 or so mixed driving.

seems to be more then me. i had 1/2 tank today im not 1/4 tank and 45 miles driven. seems kinda bad for not speeding or launching off the light or anyhting

What about colder plugs and a colder thermostat? Do you know how much knock you have if any?

gm gas gauges suck, figure out your mileage by hand.

"Maybe its bad gas"

i have ngk tr55's 180* t-stat. fuel leak not that i know of.

i doubt its bad gas, cuz iv tried different stations and its been this way for a while now. just starting to hurt the pocket more now that its getting closer to 4$ a gallon

Do you live in a larger city?

the only fuel leak that i could think of would be the sending unit next to the fuel pump in on the gas tank. when i pulled the tank and cleaned it i might not of getting the black cylinder pushed down or locked in the right way? and yes i live in mesa,az its pretty damn big

18.6 city with warm ups and cold weather driving. 29 highway.

That is why you get bad mileage, its called traffic.

i dont drive in much traffic at all. i live on the far outskirts of the "big city" lol

ill have to fill it up tomorrow before work and hand count the actual mpg i guess.