+1. Always heard it's not good to overfill.

 

Just got back from a 250 mile trip up I81. Cruise was set at 73 and I got 27.1 by the time I got home. That was with the A/C on the entire way. On the way down I avg'd 26.4 same speed. At highway speeds you almost always save gas by having the A/C on over the windows down.

 

Wow is their something wrong with my car? When i first got it the computer read 9.3mpg, 160 miles later its only saying 12.4mpg. And thats with a light foot. I havent done any highway driving yet though. Im seeing people doing burnouts and flooring the pedal getting better results then me..

 

Pretty good Ghost!

What percent of City/Highway do you do?

 

It used to be about 50:50, but since I've moved "up north", its about 90% city...but my commute to work is only 2.5 miles on a back road now. I fill up about once every 11 days.

 

OK, thanks Ghost!

Sounds like the GT's are getting good gas mileage. Good to know since I've got one on order!

 

I have 3.55s and on my trip to Georgia I was at 24.5 mpg with the cruise set at 70 mph and rpm's just over 2000. City is roughly around 14 or so. I'm getting ready to put her back in the wind for Georgia thursday night.

 

It's just going to burn off the overfill. Nothing sinister.

 

we have a local restraunt all the armers go too and i've come to a conculsion that fi you overfill more than a quart it will start to cause pressure which could reuslt in an explsion or..since the oil plug thing is made of aluminum (isnt it?) it could just shoot outta there and you could loose all your oil...but idk

 

My last fillup was 19.8 mpg and that was in 50/50 city/highway driving. I guess the 7 qt of Pennzoil Platinum 5W-20 didn't have an adverse effect on gas mileage.

 

Yeah, I think the Synthetic oils give you a little better mileage........

 

6 qts period. any more is really a waste. The 5.4 is the same. The mark on my dipstick is wrong on the stang, and my 03 f150 as well.

 

07 5 sp man w/ 3:31, ac on and 2k on the odo:

strictly hwy w/cruise running 75 mph - 23.7
70/30 hwy/in town with mostly wot around town - 18.2

these are true #s meaning filling up and dividing miles by gas used.

I expect the #s will go up once the motor wears in about 7k miles.

 

My latest fillup is 23.1 mpg based on mostly highway driving and almost 100% A/C usage. It looks like my car is getting the "right" gas mileage. I'm not sure how much better it will get as the engine is worn in. I already switched to Pennzoil Platinum at 1000 miles.