2004 grand prix MPG ?

[Rudy1999 250]

I curious about the MPG on my 2004 Grand Prix. I am running it on the highway with the cruise right between 76-80 mph. I am only getting 24 mpg? i had some people tell me the yget up towards 30 mpg. I have 91,000 miles on it and i am the orginal owner. Here are some stats on it.

3800 v6
K&N drop in
amsoil 0w30 SSO
tire pressure 35psi in front 40 psi rear.

any imput would be appreciated.



Thanks

 

[JustinH]

That sounds like good gas mileage for a 3800 v6. It also sounds like you are running too much tire pressure.

 

[ls1mike]

For between 76 and 80 that is good.

 

[Quattro Pete]

Originally Posted By: Rudy1999 250
i had some people tell me the yget up towards 30 mpg.


Maybe at 65 mph.

 

[dwendt44]

the high on my 05 was 36 under ideal conditions-55 mph. and other stuff.
35 lbs. in the tires.
synthetic oil with some miles on it.
O.S. filter.
AC off.
warm day-straight road.

 

[Rudy1999 250]

Well i can swear that in use to get 27 in my dads old 1998 Reagal GS and thas was running through Canada with the cruise at 80 ? who knows ? i just put new NGK plugs in it. thanks for the input.

 

[El_Schaf]

I can say I have done some considerable hands on research on this. At 70 mph, around 70*, you will get 30 most days.

In the winter time, at 68mph, you may average 28-29.

At 76-80, you will be getting 24. Above 70mph, mileage drops off significantly.

As stated above, in good summer weather, at 55MPH, 35mpg is absolutely achievable.

During the winter, on days that I am running late, it is around 15* and drive 80MPH to cut 10 minutes off my 90 mile commute, I can expect 22-23MPG.

Your engine is performing as it should MPG wise, or rather, it is performing like mine.

 

[Slippery_Pete]

I can get just over 30 in my Regal GS cruising at 60 to 65

 

[tomcat27]

I've had 3 of the Bonnevilles and also ran a Buick Park Ave.(actually larger than a GP) and have normally gotten 28-30 at 70-80 around 26 running 90; and maybe 24-25 running 100. each of those speed runs was for many hours (essentially all day running at that speed)

 

[El_Schaf]

This Morning, 44* at departure and 48* at arrival 90 miles later,

66MPH averaged 31.5 MPG

 

[wtd]

I'm only averaging about 23mpg in my 2004 Monte Carlo SS Supercharged. Its rated for 28mpg on the highway but on a recent 400 mile round trip on interstate running between 70-75mph, I only got 23mpg. This was with a recent tuneup with everything but plug wires. Car has 90,000 miles on it.

Wayne

 

[UNC038]

In my super charged Grand Prix (192k) I normally average 22-23 in the winter and 24-26 in the summer. It's traffic that influences my mileage so much since my car is rated at 18 city, also the fact that I like to drop the hammer sometimes. In the above cases a tank lasts me 7-10 days, so there's quite a bit of cold starts in the mix.

On a dedicated long trip I can pull low 30's hwy.

Old EPA rating: 18/28 city/hwy
New EPA rating: 16/26

 

[sciphi]

The W-bodies will get worse fuel mileage than an H-body with the same engine due to differences in engine computer programming, tires, aerodynamics, and exhaust setup. The W-body Regals typically get better fuel economy than a W-body Grand Prix. Both give up fuel economy to an H-body Bonneville or LeSabre, or a C-body Park Avenue. The Grand Prix is meant to be the "sportiest" of the cars listed above, and has the widest tires and more aggressive computer programming than most of those cars.

26 mpg highway sounds about right for this time of year and your car.

I usually get 32-33 mpg highway in my H-body LeSabre due to a tall final drive ratio and skinny tires. Best I've ever seen was 39 mpg on 3 occasions during a heatwave last summer, with some basic fuel-saving techniques used. In-town I'm seeing 20-22 mpg, since it's urban-jungle driving.

 

[saberz]

I would average about 28-30 back when I had my 01 Impala 3800 Series 2. Did a trip to Steelton PA and back(175 miles each way, and had plenty of gas to drive the rest of the week to work which is 30-35 miles). Roughly 380-390 miles to a tank was average on long trips. Short trips I would be 340ish. Mind you this was before the Ethanol blending. Not sure what its at now but its still well over 300 as my brother doesn't cry about the gas like he did with the Jeep.

 

[Kaboomba]

MPG for my Park Ave has slipped a bit over the last year, I think due to combination of old plugs and old O2 sensor (tune-up in progress here).

Worst recorded for me was ~16mpg (LOTS of 2-10mi trips in 0-15F weather--wife driving--I usually pick up 2mpg!)

Best was 29.9mpg for a 15 hour day of 78mph, 90-100F amb temp, climate control set to 72F (hooo ya).

Normally I get 300-320 mi from 14gal E05.

K