Another gas mileage post

[tblake]

Bob, I love the BS flag guy! Great touch!

To the OP, have you checked the FPR vacuum line for fuel contamination?

[a_alyte]

No, I have not checked the FPR vacuum line for fuel contamination, not sure how to do this yet. The Hayes manual shows a little white on a plug as being normal after some use. I understand that the Avalanche has newer technology, but what about my '98 Grand Cherokee, this vehicle does 150 miles on a 1/4 tank & has close to 200k miles on it, & is two years older? This is what led me to believe my mileage was bad! Also, my relative drives the same distance & also uses a 1/4 tank on a '02 Bonneville.

I'll look into the vacuum line recommendation soon as I get a chance.

[tblake]

I get just over 150 miles out of half a tank of gas on my GTP with my mods, on winter grade gas, in mixed driving, mainly city. (just to put your milage into spec).

Check your vacuum line at the FPR for gas. It may be leaking.

[Schubiez]

You guys are all lucky, I get a big whoppin 200 miles out of my full tank! Once in a great while my car will be nice and give me 300 though but i've only seen it happen a couple times and i've owned the car since 2005! BLAH!

[serge_saati]

Originally Posted by Schubiez

You guys are all lucky, I get a big whoppin 200 miles out of my full tank! Once in a great while my car will be nice and give me 300 though but i've only seen it happen a couple times and i've owned the car since 2005! BLAH!

On highway, city or mixt?

[tblake]

And what Year of car? GT, GTP, or SE?

[serge_saati]

It could be also an LE, STE, GXP.

[SNKPWR]

Mixed driving I get about 23...all 70 mph I get about 30 mpg...but i definitely agree on not trusting the gauge, mine reads full until about the last quarter tank or so...

[serge_saati]

Originally Posted by SNKPWR

Mixed driving I get about 23...all 70 mph I get about 30 mpg...but i definitely agree on not trusting the gauge, mine reads full until about the last quarter tank or so...

That's is excellent! 30mpg at 70mph and 23mpg mixed is excellent for a grand prix.

So when you make 300 miles with your tank, I assume that you don't use all your fuel? Maybe 80% or something. Cause you've a 16 gal fuel tank.

But when you do 200 miles in a tank, it contradicts your gas mileage. Gas mileage should not fluctuate that much.

[SNKPWR]

Originally Posted by serge_saati

That's is excellent! 30mpg at 70mph and 23mpg mixed is excellent for a grand prix.

So when you make 300 miles with your tank, I assume that you don't use all your fuel? Maybe 80% or something. Cause you've a 16 gal fuel tank.

But when you do 200 miles in a tank, it contradicts your gas mileage. Gas mileage should not fluctuate that much.

Yeah at 300 miles it takes 11-12 gallons

[serge_saati]

So it's very good, 26 mpg. You doing 300 miles with 70% of tank. You can do 415 miles until it goes to empty.

[SNKPWR]

Originally Posted by serge_saati

So it's very good, 26 mpg. You doing 300 miles with 70% of tank. You can do 415 miles until it goes to empty.

actually it almost always comes out to 22.5-23 when I fill up, so maybe 13 gallons at 300 miles, or maybe I just usually fill up before 300 miles...

[serge_saati]

For mixed driving 23 is good. And if you're using A/C, it's normal that consumption increases a lot (20-30% more). So in summer, it'll increase.