metroplex

I recently did a lot of highway driving and my gas mileage was just a few
tenths under 23 mpg (07 GT, 3.55s, manual). I used the A/C the entire time.

Is this decent/normal gas mileage or could I take it easier on the gas? The car has less than 2000 miles on the odometer, and I'm using 7 qt of Pennzoil Platinum 5W-20 (just changed the oil).

The 2008 EPA rating system estimates the 07s at 15/23, so it seems like I'm just about on the dot. I normally get 19 mpg with 50/50 city/highway driving, which is about half-way between 15/23.

Glenn

you must have been doing over 80mph most of the time??

Juice

I have an 05 vert, gt with auto and 3.31. On a long trip to Colorado, I saw a best tank of 23.5 and a worst of 22. Around town and going to work I see 20-21, depending on how hard I get on it.

theedge67

7qts? It only takes 6. Are you running one qt over or was that a typo?

metroplex

I was moving with the flow of traffic, so it was about 70-80 mph. My speedo reads 3 mph faster than the GPS...

Steve: Yes, I filled it to 7 qt. It takes about 6.5 qt to reach the mark, and I figure I might as well just dump the other 0.5 qt in there.

Juice: I have a hardtop coupe and I use 87 octane gas. It's totally bone stock in terms of mods. I never touched the PCM.

karman

Uh, it is okay to have it "below the the mark" as much as half a quart.
I've never seen anything that says it is okay to OVERFILL.
Half a quart below YOUR mark would be 6 quarts.
"• If the oil level is between the lower and upper holes, the oil level
is acceptable. DO NOT ADD OIL.
• If the oil level is below the lower hole, add enough oil to raise the
level within the lower and upper holes."

davam1

Just took a trip to Pa. from Ct. 440 miles. Trip computer said I got close to 29 mpg (07GT ,3.31, 5spd.). I haven't tried to compute it myself but if its reading properly, that's more than I ever expected. I tried to use CC at 65 mph most of the way and tried to lean it out when I could. AC on most of the way.

orangeRcode

I recently got around 13 mpg. However, that was doing 3 15 minute sessions at the road track with a race tune and high test fuel. With the 91 tune, I generally get around 18-20 in town driving if I keep my foot out of it.

Fords4Ever

Sounds like you're right on. On a recent 800 mile trip I averaged about the same 23-24mpg doing mostly 80mph w/air on.

I also did a previous experiment on a shorter 90 mile trip. I reset the mpg before getting on the highway and did a fairly constant 70mph with the cruise control and a/c on and I got 25.1mpg

metroplex

My GT doesn't have the IUP, so I calculate it the old fashioned way: Miles / Gallons of gas used to fill up the tank

I played with a trip computer in a rental 07 Taurus and I thought it was pretty neat. Had I played with a trip computer prior to ordering the GT, I would have gone with the IUP but I don't have any regrets.

Karman: Engine oil fill levels aren't an exact science. I figure the 0.5 qt would feel lonely on the shelf, so I dumped it in. If I notice a hit in gas mileage, I'll go back to 6 qt for the next change.

procopius

I'm approaching 5k miles and I think my mileage has improved slightly since break-in. I'm getting maybe a little above 25mpg at 75mph, CC on, air off, measured by the computer. And for the record I put in 6.5qts for an oil change + filter, that puts me a little below the upper hole on the dipstick. I don't think oil level would affect MPG unless it was drastically high or low.

ShowGT

I filled up this afternoon, just over 16K and car is averaging 20.1 on the display.

GRAYPNY

Personally I would drain a quart of oil out, but that's me.

Since going back to the 3:55's I'm averaging 22.5 but not having as much fun!

Falchion

What percent of Highway/City driving do you think you're doing? 50/50?

metroplex

I believe our engines have a windage tray (possibly even a scraper?) so the excess oil shouldn't have an effect on horsepower or gas mileage.

I also shift at about 1500-2000 RPM on the road and get 18.5-19.5 mpg in mixed driving. When I drive like this, a puny Toyota Echo can easily pass my car on the road.

Fords4Ever

Rich, when did you switch back to 3:55s and why? Mileage?

GRAYPNY

Poor install = they gave up.

metroplex

I'm sorry to hear that. For what it is worth, I rather like the factory 3.55s on my 07 GT. I wish I had gone with the 3.31s for slightly better gas mileage as I don't really need the acceleration.

RaGsHoCkEy88

ford made no points by making 3.55's optional. glad my 05 came with them stock

GhostTX

Since I've owned the car:
Best mpg - 26.1
Worst mpg - 16.3
Overall average mpg - 21.1