Poor Mileage Please Help!!!

mustanggt2OO5 · 05-22-2005

Hey,
I need some help in a hurry I got a 05 gt.
For the first two weeks after i revieved my new stang, i was getting the posted 19mpg in the city. Now, I'm down to 12.9 mgp. I have put only 5,000 miles on it. What is the deal? Has anyone else noticed a big lost of mpg?
I thought at first that it might be just that I have gotten so crappy gas but it has been like three fill ups since I noticed the drop in mpg. I only use the middle grade gas and have never put the cheap stuff in my stang.
I talked to the dealer and he had no idea and asked if i had been stomping on the pedal but I haven't been.
I hope that someone can help me or at least give me some ammo to talk to the dealer about! Thanks

kj_cinci · 05-23-2005

My MPG is getting better as my miles are racking up... I have done some stuff to my engine though but am currently at 18.5 MPG at 2000 miles, about two miles more than I had with 700 miles on her...

Something must be wrong if you're not on it ALL the time with under 13 MPG... Maybe your car was at an angle when you fueled it one time or something else went wrong and the computer is confused? Are you fueling more often now or just basing this on the info center MPG number? I'd reset the computer and start from scratch maybe it catches up and will work properly and show you the 19 again?

mustanggt2OO5 · 05-23-2005

i have tried everything and i reset the gauge after every fill up. and the gas station is flat.
i have noticed that im having to fuel it up more often then before.
any more help would be great!
thanks

turn2 · 05-23-2005

Well there could be a gas formula problem. The gas companies here in California change fuel types for summer and winter time. If they are putting alot of alcohol in the fuel that could cause it. A gallon of alcohol does not have as much energy as a gallon of pure gasoline. You computer in the mustang knows this and adjusts the air fuel mix accordingly. Whitch could explain bad mileage.

Shadowfax1 · 05-23-2005

I am still waiting on My 05 Gt to come in, so I can't help you from my experience. But a friend of mine has an 04 GT and she started getting worse and worse gas millage as time went on. Then her gas gauge started acting up. When she took her car in to the dealership they put a new gas tank in and replaced the hardware in the tank, and she started getting 20 plus MPG on the highway again. Maybe this could be a problem in your car too. I don't know exactly what the problem was with her car because I was just hearing this second hand from her and she could not remember word for word what the service dept said. I hope this helps and good luck fixing the problem.

gkaufman · 05-23-2005

I wonder if 89 octane is hurting you, our cars are designed to run on 87 octane, but im not sure if thats the problem. I drive mine hard a lot but I always end up getting 24 to 25 on I81 (75-80mph) every weekend and about 19 - 20 when i drive to work during the week (avg mph something like 37mph), and thats mostly backroads. The lowest mileage i have seen only once was 17.5. I feel for you though with gas prices the way they are.

Georg

d6_05GT · 05-23-2005

take it to a tech.
Hell even getting on it frequently... that would be hard to do.

Waxed'05 GT · 05-23-2005

Amoco Ultimate ads have made consumers believe higher octane gas is better quality. In fact it is not... Use 87 Octane and see if that helps, otherwise take it in for a check up. Only use a higher octane if modifications require you to do so. With higher octane you are also leaving power (hp) on the table, higher octane fuel burns slower to compensate higher compression engines. (There is a thread on here that speaks of it) Anyways, its your car, do what you like. I know someone with a newer base model Eclipse that only uses premium because they believe it is "better gas". I am hoping for a class action lawsuit against Amoco

..my two pennies

teknight · 05-23-2005

I've only used the regular unleaded in mine so far. That's not saying much since I haven't even owned it a week yet. However, in my 2000 Ranger with 3.0L V6 I was getting a lot of pinging during acceleration. Once I started filling up with the "good stuff" the pinging went away. I'm not a mechanic so I can't explain it but it did make me feel better.

Waxed'05 GT · 05-23-2005

The "pinging" is what is called predetonation. A slower burning fuel, i.e. higher octane helps to prevent predetonation. You should have had the timing adjusted though, imo.

tw0scoops123 · 05-24-2005

You shouldn't be using anything other than '87. If you use a higher octance gas regularly, you wil likely have some wierd after affects. Who knows if thats what you're seeing. But the fact is if it was ok to put highern octanes in, the manual would say thats ok. But it doesn't. Just says 87 octane. "Some metallic based compound or additives found in premium fuel could damage or deteriorate the emission control system." It says something about canada having higher amounts of it in premium, butI'm gussing that goes for the US too. So putting something in your car that's not recomended isn't a good idea.

Might as well play it safe and save some money and just start using the 87 octane.

malecasta · 05-24-2005

Buy a Prius.

If you are running 2-3 miles less a gallon than Ford's inflated factory promise, that adds up to about $6 a fill. Cost of being cool, my friend. Put the petal to the metal and let the straights worry about their gas mileage.

tw0scoops123 · 05-24-2005

Quote:

Originally Posted by malecasta

Buy a Prius.

If you are running 2-3 miles less a gallon than Ford's inflated factory promise, that adds up to about $6 a fill. Cost of being cool, my friend. Put the petal to the metal and let the straights worry about their gas mileage.

HAHA well said!:thumbup