FLAstangx3

Re-read Doctor Q's post above. You DONT need IUP, just push the stupid reset button on the odometer. Be consistant with your checking. IF you are correct, then it's probably just a sensor. I'm betting your not. Drive it like you owm it, not like your renting it. If it doen't improve then do the reverse.

Tampa07GTCS

That 10miles of bumper to bumper traffice took me 30min

metroplex

Re-do the calculation in normal driving (as little bumper to bumper traffic as possible).

Tampa07GTCS

ok...another 50miles today of straight interstate...no stop-and-go...got 14-15mpg. How are some people getting 19-25mpg on the interstate???

theedge67

How did you calculate it? Not saying you are wrong, but if you filled up the tank, then drove 50 miles, then filled up again, you won't get an accurate estimate due to variations in how full the tank was to start, how much you put in after the run...etc. When you average it out over an entire tank you get a much more accurate result.

That said, people are getting 25mpg on the interstate because that is what these cars do. Something is wrong with your car if you are getting 14-15.

Tampa07GTCS

I filled up the tank this morning...15gallons... drove 50 miles on the interstate...used up a quarter of a tank = 3.75gallons. 50miles divided by 3.75 = 13.33 MPG... = Something is wrong!!! I rounded up when I said 14-15 assuming that they is a lil user/guage error!!

RobK

So you stopped after the 50 miles and topped off with 3.75 gallons? You can't go by the indicated volume on the gauge. They're simply not accurate between full and empty.

karman

So you filled it, then drove, then filled it again after 50 mi.
Even if you put in a little more the second time (1/2 gal.), you still haven't broken 15mpg.
I've never gotten less than 17 ever.
Something is wrong for sure.

Tampa07GTCS

Ok....so now I have double checkked my problem within this weekend, i know it is something. Has anyone else seen this problem before? Anyone have a suggestion on what to tell the dealership the problem could be? .... I love my car....I just wish I could figure out this problem!!

Tony Alonso

I would suggest you describe the symptoms you are seeing to your favorite service department. I think it is important to note what gas you typically purchase, your driving habits in terms of selected gears and throttle usage, and the typical length of your commutes.

From there, I would assume your car's PCM would be checked for any outstanding codes, the air/fuel ratios examined, and other standard diagnostic checks related to drivability issues.

It would be difficult to suggest what a potential problem might be without further detailed information about the engine's operating state.

DoctorQ

Thomas: After you drove 50 miles, did you pull into a gas station and fill up (i.e., you ADDED 3.75 gallons of fuel)... or after driving 50 miles, did you look at your gas gauge (which must have been on 3/4 full) and assume you used 3.75gallons? This is an important point as the guage may not be calibrated to show exact fuel... you'll need to divide the 50 miles by the amount of fuel you added after driving the 50 miles.

Tampa07GTCS

will do...will fill up in the morning

theedge67

I'm not sure if you've tried this but the only way to calculate accurate mileage is over the course of an entire tank of gas. Run it until the gauge is almost at E, then fill up. divide miles driven by total gallons purchased. This gauge estimating stuff is no good, the gauge is not exact and can be several gallons off.

metroplex

Steve is right.

If you want to accurate calculate MPG, start from scratch and max out the gas tank. Reset the trip odometer. Drive around until you need to fill up on gas. Record the # of miles from the trip odometer and the # of gallons needed to max out the tank. Miles / Gallons = MPG. People recommend taking the average of 3-5 fillups, but I keep a log of every fillup and just plot it on a graph trying to find correlations between ambient air temperature and driving schedule to see its effect on gas mileage.

FLAstangx3

This may sound rediculous, but. Is it breathing? I know it is new, but, open up that air box, and give it a check. You just may have a bad filter.
Sounds to me like it is an air/fuel ratio problem. Of course if it were mine, I'd fix it right: CAI/Exhaust/Bama tune!! Then she'll, breathe, perform, and you WILL get the best mileage ever, because it will be done right. IMHO

Twisted_Reality

I would say you do have a problem. I got over 25 mpg (yes it is according to the computer but I can say mine is close to accurate) yesterday from Lakeland to Clearwater. I don't know if you are using the cruise control or not, but I do know it makes a few mpg difference when I do. (Heavy foot on overpasses and overtaking)

Also, I get around 16 mpg during my daily commute up and down US 19.

Tampa07GTCS

I always run the car everytime to almost empty and reset the Trip computer, so that I may calculate my MPG. I am averaging 15gallons per fill-up and 230total miles on a tank = 15.33MPG. Everytime I drive I-4 & I-75 I use the cruise control, but on I-275, people drive to crazy to be able to depend on a set speed.

Tampa07GTCS

I do believe it is breathing correct... I replaced the stock Air-filter due to bad MPG on the 4th day of ownership. I put in the K&N air filter. I will be putting in a CAI/Tune/GTA Axle backs as soon as the dealership fixes my problem. I don't want them to blam any problems on Mods!!

FLAstangx3

Don't know which dealer you use. BUT, regardless, of the big three in Tampa. Go to Brandon if you do not get results from your selling dealer. Not only is their service performance oriented, being the largest ROUSH dealership, they have taken care of a lot of us TMS guys.

Tampa07GTCS

Brandon Ford is actually where I purchased mine. I have a family member there who is the Fleet Manager. I will be takin it there Wednesday morning! Hopefully this doesn't take forever to fix! Last time I took it in I got a base-base-base Ford Taurus, man did that day suck!