Ebony5.0

Okay, I know that we didn't buy the 5.0 for mpg. I also know that one sure cause of low mpg is lead foot. Assuming that I'm not driving like a heathen all the time, why is my city mileage 6 whole mpg lower than the 16 mpg that was advertised? For purposes of informing your opinions, I'm running 3.55s. I'm struggling to get 10 mpg. Car has 300 total miles.

Thoughts???

28.

You reset your mileage meter? I heard something about this elsewhere

fritzOSU03

Allowing the car to sit and idle while you stare in awe will reduce that magic number on the display.

Dougxox

the longer you run the car the better miliage you will get as it breaks in, about 1k miles will about do it. Also try to keep you foot out of it..

WildPony619

You need to keep driving more. I had a similar ssue when I first got my stang. I couldn't get higher than 13 MPG for at least up to 350. After about 500, my MPG went up and up more. It has to do with the computer calculating based on the amount of miles you've driven to what you've used in gas. It gets more and more accurate after 1000 miles. I'm averaging around 17 and 18 MPG driving mostly city and stop and go on the highway and I'm at about 1500 miles.

JobeNole44

My first tank I got 14 doing the same driving that would yield me 18.5 with my 2006 GT. Now, at about 1300 miles, I am currently at 18.5 MPG on this tank and I got averaged 24.2 for several miles on the highway going 65. With 3.73s I dont expect to get the 26 advertised on the highway. Also, here on Orlando it is low 90s with 90% humidity. Probably the worst case scenario when it comes to mileage and engine efficiency in general. I am sure I can average around 19.5 combined when in the spring, winter, and fall here.

Bert

I think you are having too much fun with your new 5.0!

Or maybe it just needs to break in a little? I'd suggest you give it a few hundred more miles before you worry about it.

When you are ready to really check it, fill up the tank and write down the odometer reading, and reset the MPG in the computer at the same time . . . then take a nice easy highway cruise or whatever you want to do; then go back and fill the tank so you can manually calculate miles per gallon and compare it to what the computer says.

. . . if it's still real low, I'd have it checked out.

Ebony5.0

Makes sense. I'm in DC and it's hot as hell here now. I'm not using the mustang's computer to calculate the mpg because the computer is notoriously off. I'm calculating at each fill up (and there have only been two so far). I will admit that I have had the car running while sitting still while I was familiarizing myself with all the sync stuff. I'm glad to hear that the mileage gets better with age.

Lancel

Wow, you must have a heavier leadfoot than mine. I got my car down to 13-14 MPG and I thought I was doing bad. Have you been shifting up a lot? The car is awfully quiet a lot of the time, I frequently check the tach to see how much RPM the engine is really running and have taken to shifting between 2-3k RPM and keeping it between 1.25k and 2k RPM (I downshift if it ever hits 1k). Now that I'm getting used to it I generally keep it in a high gear, 6th for anything 55 and over, 5th if I want more control, 4th to render the guy in front of me as an object disappeared in the cloud of dust behind me.

I love this car.

Presently up to roughly 15.8 MPG, nearly 450 miles. I do have 3.73s mind.

GRABOID

WTF is right
I could get better than that with a full day at the strip . If manual try shifting out of fourth on the highway.

Five Oh Brian

Fuel economy improves after car is completely broken in (1-2K miles). Driving style plays a big part, and the hot weather isn't helping. Gas blended with ethanol (up to 10% legal here) will reduce mpg also.

coffeejolts

10 MPG is pretty bad. Using 10% Ethanol gasoline in Atlanta traffic, I average 18-20 MPG. In pure highway driving, I get 29 MPG.

I am running top tier 93 octane E10.

MRGTX

So... yes. Listen to Bert!

IIRC, this is exactly what the owner's manual tells us.

cdynaco

You have to reset everything - mpg, avg speed, gallons used, etc. I didn't for awhile and was doing partial fillups and the computer was no longer accurate to hand calc. Full fills and resetting everything brings the computer pretty accurate for me.

Lancel

There is that too. The manual does say that you shouldn't pay attention to the MPG during the break-in period, warning that it will be inaccurate.

Ebony5.0

Good advice from all. You're definitely easing my concerns, which weren't too big to begin with (though if my overall mileage had stayed 10 mpg for too long, I'd have been a little miffed). I think the car's mileage will increase after break in. Also, while I was waiting for my ordered car, I was driving my girl-friend's mini cooper, which has to be kept in a really high rev range to have any pickup at all. I'm not used to having so much torque on board.

Overall, I'd consider my driving style moderate. I let it out occasionally but normally upshift between 3500 and 4500 rpm. Also, when I'm over 60 on the highway, I'm usually in 6th.

I also end up doing partial fill ups because the low fuel light comes on at a quarter tank. Then the thing tells me I have 50 miles to empty. It makes me paranoid.

Bert

Your "normal" is closer to "letting it rip" for me . . . also depends on throttle, of course you can slowly let it wind out with small throttle openning and get to 3500-4500 RPM, but usually if I'm revving it that high it is with pretty heavy throttle/acceleration . . . for normal everyday driving, I'm usually upshifting around 2000-2500 RPM . . . try that and you'll probably see an increase in mileage even before it is broken in

MattR

I got 15mpg on my first tank. That was all city and short trips in 90+ temps with the AC on. I also have a Shelby. So I'm a little surprised how low some of the 5.0 are doing, but I'm sure you guys will do much better than mine once your broken in.

I didn't use 6th gear for the first tank either. Seemed like I was lugging it to much.

cdynaco

That's especially important during break in. Rev that sucker, vary the rpm's, don't lug it. And I take mine to redline (at least) once a day. No carbon for me!

Bert if you're shifting at 2000 all the time you might want to rethink that. Nobody's gonna want to buy a loaded up ol' lady's engine.

Lancel

Psh. I let it rev to 4000 RPM in 1st usually. I shift up at 2000 RPM when I'm at cruising speed, otherwise it's more like 3000-4000 RPM. A few times now I've really punched it, I've bounced off the rev limiter twice now. Hehe. I think it's actually getting better at punching it now, or maybe that's just me picking better gears.