Why am I getting such bad fuel economy?

[Random Variable]

Three weeks ago I purchased a 2004 Pontiac Grand Prix GTP--a automobile that gets supposedly 18 MPG in the city and 28 MPG on the highway. Well, since I got the car I've been averaging 15 MPG (15.1 to be exact). And I don't live in the city.

I should have gotten the GT2 model. :disgust:

 

[Quixfire]

Are you running you a/c? Those averages are with no accessories on, like a/c.

 

[BigSmooth]

Have you checked your tire pressure?

 

[Random Variable]

Originally posted by: Quixfire
Are you running you a/c? Those averages are with no accessories on, like a/c.

I has been awfully hot these past few weeks. Will the fuel economy improve as the weather cools?

 

[Quixfire]

Originally posted by: Vespasian

Originally posted by: Quixfire
Are you running you a/c? Those averages are with no accessories on, like a/c.

I has been awfully hot these past few weeks. Will the fuel economy improve as the weather cools?

It should if your not running your a/c, but if you live in a northern state winter weather will also decrease you MPG.

 

[Random Variable]

Originally posted by: BigSmooth
Have you checked your tire pressure?

I haven't checked it myself, but the onboard computer hasn't reported any problems.

 

[conjur]

A/C won't affect it too much...esp. if it's NOT city driving. So, you do a lot of highway driving? Hell...that would be even worse unless you're averaging like 90mph! :Q

 

[freebee]

A new car may have to be broken in....fuel economy will suffer as a result. You will also see this with any major powertrain modifications and/or loss of power to the battery where the car will have to "relearn" various operating parameters.

Also, as was mentioned by other members, check tire pressures and AC, etc. However, even with those factors, you should still be in the 20+ mpg range. If it does not imporve by 3-4k miles, take it to the dealer for evaluation.

 

[AbsolutDealage]

Originally posted by: Vespasian

Originally posted by: BigSmooth
Have you checked your tire pressure?

I haven't checked it myself, but the onboard computer hasn't reported any problems.

The computer will only complain if one of your tires is low... I would check it anyways. Besides that though, it's probably just the A/C.

 

[BigSmooth]

Originally posted by: Vespasian

Originally posted by: BigSmooth
Have you checked your tire pressure?

I haven't checked it myself, but the onboard computer hasn't reported any problems.

You might double-check it... I think underinflated tires are one of the most common causes of poor fuel economy. Also, clean out your trunk/back seats if you tend to carry a lot of stuff back there.

 

[Ladies Man]

1. Take the emergency brake off
2. Take the 4 dead bodies out of your trunk... extra weight lowers mpg
3. Lose 400lbs.... not so much for the fuel economy i'm just really concerned about your weight problem 😉


I wouldn't worry about it yet.... Try using different gas stations, some have additives in the gas to make it burn purer but it lowers mpg.... If you have a lead foot give it a break for a tank or 2.... After a few thousand miles, 3k when you go to get your oil changed, have the dealership look at it.

 

[Ryan]

That really isn't that bad. The MPG figures should go up once the engine has been broken in.

 

[Random Variable]

Originally posted by: rbloedow
That really isn't that bad. The MPG figures should go up once the engine has been broken in.

The first few days I was averaging only 13 MPG, so maybe it will go up over time.

 

[maziwanka]

the economy right now in general is down. give it a while and things should steadily get better.

 

[BadgerFan]

Originally posted by: Vespasian
Three weeks ago I purchased a 2004 Pontaic Grand Prix GTP--a automobile that supposedly gets 18 MPG in the city and 28 MPG on the highway. Well, since I got the car I've been averaging 15 MPG (15.1 to be exact). And I don't live in the city. I should have gotten the GT2 model. :disgust:

Doing lots of hard acceleration, being in the break in period, tire pressure, AC, having the ECU "learn" the engine all have an effect on the engine. If you are driving a lot on the interstate, and your mileage is less than 20 at your first oil chance, you might want to have a dealer look at it under warranty.