Lousy Gas Mileage! HELP!

[viperos]

well, I bought gas last night, and figured out my mileage... I'm getting just over 14 MPG!!! I commute about 10 miles a day... more than half is freeway... I just changed my fuel filter, cap/rotor, and did general tune up stuff... I could probably stand to change my oil again... been just about 2200 miles... I shift when my manual tells me to... at 12mph, 24, 35, 45 (works out to about 1950RPM) but I've tried shifting at 2200, and 2500 as well on previous tanks...

-should I cave and buy one of those "add 15% HP and increase gas mileage little gimmicks?

 

[Joes95GT]

What's your fuel pressure set at? You can pick up a MPG or two by dialing that in. Your car is still fairly stock, wait till you put a set of gears in, that will give you a few more MPG too. When I was going down to North Carolina this summer on vacation I got 25 MPG cruising at 2800 RPM in 5th with the air on, so shifting at a low shift point does next to nothing for gas mileage purposes. I shift my car around 2800 1-2 and 2200 for the rest of the gears and I get 13 MPG, the only difference is that I drive the car 10 miles a day, once a week, so 13 MPG is great for what I do.

Joe

 

[95GTvert[bv12]]

when i was only driving 10miles to work i was getting 16mpg now i drive 25miles and i get around 23mpg.

 

[viperos]

well, fuel pressure is stock... but what I don't understand, is during the summer, I was getting close to 18 MPG... and I thought that was bad... jeeze! (I'm getting about 22-28MPG w/ my taurus though...)

 

[Joes95GT]

What grade of gas are you running? For how many tanks have you been getting such lousey gas mileage? If this was your first tank, you probably just got some junk gas. If that is the case, try another place. Also, knock the timing back to 10 degrees (if its not already) and run 87 and see what kind of gas mileage you get. You might be using a higher grade than what you need.

Joe

 

[viperos]

well, 89 octane w/ timing just over 13... so I'm right where I need to be on gas... could have been a bad batch I guess... but 76 has never done that to me before... I use Chevron/76 depending on which one I'm closer to when I run out... I guess I can try retarding the timing... but I'd prefer not to... for that once a week instance of the ricer at the stop light

 

[Car Nut]

FYI:

I used to drive about 20 miles to work (18mpg), until they moved about 10 miles from my house. The 20 mile commute was mostly on a highway and there were very few traffic lights, so I got to spend most of my time in fourth and fifth gear. Now, my 10 mile commute is full of traffic lights on two lane roads (scenery is nicer and less stress, thank god), but now I only get 14-16mpg. My new commute keeps me mostly in second and third gear, I hit nearly every stop light, and fourth gear only happens for a mile or two.

I got a bit paranoid about my decrease in gas mileage until I took a long trip last month (mostly in fifth on highway) where I averaged 22-23mpg. My next long trip was on an Intersate at about 75mph which netted me 25mpg.

In-town traveling can suck....literally! I wouldn't worry too much until you test your mileage on a long trip. I wouldn't follow the manual's shifting recommendations. I usually shift around 3K until around 4th, but I'm not flooring it to get there, just driving casually. Just shift smooth and use a good bit of that rpm range....gotta let the engine's legs stretch.

 

[viperos]

so I guess I will go back to shifting around 2500-2750... that seemed just fine... no bogging going up hills or anything.

 

[95GTvert[bv12]]

your o2 sensors could be bad.

 

[viperos]

would bad O2 sensors be causing that lousy of mileage?? because if they aren't, I don't really want to shell out $70 for each side!

 

[91LX_5L]

I dont know gas mileage but how many Miles do you get to a full tank? how many miles to a full tank should a stang get when shifting at like 2,700rpm?

 

[viperos]

well, I usually fill up my tank when I hit 160-180 miles... and that usually ends up being 11.4-13 gallons...

 

[Ethereal Zer0]

well, I bought gas last night, and figured out my mileage... I'm getting just over 14 MPG!!! I commute about 10 miles a day... more than half is freeway... I just changed my fuel filter, cap/rotor, and did general tune up stuff... I could probably stand to change my oil again... been just about 2200 miles... I shift when my manual tells me to... at 12mph, 24, 35, 45 (works out to about 1950RPM) but I've tried shifting at 2200, and 2500 as well on previous tanks...

-should I cave and buy one of those "add 15% HP and increase gas mileage little gimmicks?

You wuss! I'm getting about 11mpg in the city here, i need a tune up though lol. I agree with the whole this summer thing though, when i drove in the city this summer i was getting about 17-18mpg. I dunno how to explain that one...

 

[Joes95GT]

would bad O2 sensors be causing that lousy of mileage?? because if they aren't, I don't really want to shell out $70 for each side!

Yes, if an O2 is malfunctioning, it's telling the processor to dump more fuel, causing a rich condition. Does the car give you any codes about the left or right bank being rich? Does the car give you any codes?

Joe

 

[94Blue302GT]

I"d check the codes, sure, but i get 13- 14 mpg with some basic bolt ons and the way i drive, what can i expect? I'll tell ya what though, driving on the highway (even chicago highways) can get me about 20-23 mpg! It's a big difference, and i think it's all cuz i have the 2.73. Oh, and i don't take it out of fourth on the highway unless i'm above 70, really no point to.

 

[viperos]

never learned how to check the codes... someone want to give me a "crash course" in mustang maintinance?

-unless you mean the idiot lights... in that case, nothing.

 

[95tealGT]

Your driving style also has a lot to do with it. I drive my car everyday back and forth to work and school. To school its about 1.3 miles and to work its about 2.4 from my house. My car doesn't have a chance to come even close to normal opperating temp and in this cold weather it just eats the gas. I never take it above 2000 rpm on these short drives either, and i'm still only getting around 10mpg.

I know nothing is wrong though because just the other week I had a full tank on just highway use and I got 23mpg. Plus we have these things called 'V8s' under the hood, sometimes they're known to eat gas.

 

[mytight95]

what plugs are you running and at what gap.
i would recommend autolite 25's with a stock gap of .045 and see if that helps, also if you have bigger tires in the reat etc. that will eat away at your mileage just a hair

jason

 

[viperos]

as far as checking the codes though... how, what to buy, where, any info on that?

-I'm using 245/45/17s in the rear... stock stuff... using OEM plugs/wires, brass (upgraded) cap/rotor, rest on the car is stock, except my 2 bolt ons... (CAI/pulleys)...

-but then again, if my car isn't warming up for my commute... that would probably explain fully my lousy gas mileage...

-and yes, those little (well, not actually) things called V-8s do suck the gas down... my little (actually, not that little either) V-6 in my taurus gets like 20 even on short commutes though...)