These rumors of gas being $4+ per gallon this summer have got me thinking about fuel economy. The DIC in my '06 GP says I get about 22 MPG. Most of my driving is on streets where the speed limit is 45, but they are still city streets so I have to contend with annoying traffic lights, etc. The website fueleconomy.gov says that an 06 Grand Prix should get 21 MPG on average.

It'll take me a while to determine the MPG of my car "manually" myself, but I'm just wondering what kind of MPG all of you have experienced with your GPs. Also, have you ever figured it out using your miles driven and the number of gallons of gas used (zero out your trip OD at fillup, then the next time you fill up, note the mileage, and use the number of gallons of gas you just put in the car as the number of gallons used), or do you just believe the computer?

Consider yourself lucky, I get about 15mpg around town.

I don't have the digital DIC in my car so I calculate mine manually after every time I fill up using the trip odometer.

One thing you can do to help your gas mileage a little is try and get the car into 4th gear when you are traveling down roads with a 45mph speed limit. My car goes into 4th around 48mph and I can use it to hold my speed around there at only 1800rpms.

my GTP gets 25mpg running around town in Perf. Shift mode with just a CAI, i love it to death, i also fill my car up each and every week (i have since i bought it)

around town i get maybe 14mpg, my DIC says 17.6 but im on the highway alot.

i put $25 in my tank everyday, it sucks. but i cant find it in me to get a different car

DIC reads 23.4 and it goes up each time I take longer trips and stay out of the pedal.

the dic pulls an average of the last 500 miles you have driven so it isnt very accurate at actual fuel consumption.

The most accurate method is to tally up the gallons used at fillup.

my gt gets 20 flat no matter what I do.

17-18 city and 19-20 hwy, gosh i need to replace my o2

I'm getting 22mpg according to the DIC. A friend at work gets 25mpg in his colorado and 26mpg in his 99 vette.

17 city and 30 highway. just a k&n filter.

well i havent checked in a while, but a co-worker that lives by me told me about a different way to take to work on a 55 mph road instead of the 70 mph hwy 35, he said he gets the best mileage if he keeps the tach below 2000, so ive been taking that way now and i have noticed an improvement on the day i need to refuel if i dont do much else but go to work and back

I get about 17-17.5 city, and about 23 highway...not sure why. Maybe because I'm not content with cruise control because someone always has to be passed...I'm anxious to get some mods in thought to improve gas mileage.

28 highway, city varies from 18-22 depending on driving conditions. My DIC sits around 24 mpg most of the time, I'm not unhappy with that average.

citys crappy because how i drive maybe 15 mpg....highway i get 29 mpg but around the 75 mph range any higher or lower and my mpg drop....basiacally because its around the 2500 rpm range and that seems to be the best for my car and what mods i have

gosh everyone here is lucky but me !!!

Not luck, you haven't taken the the steps to increase it, as you just mentioned above. Also, tuning the car will help exponentially!

I get avg of 22 on a full tank to empty, with mixed driving.

im slowly working on the steps, but my suspension comes first because its toast, then its a catless downpipe and new o2

what can i do to improve gas mileage, if i can't get my gas mileage to go above 22, i gonna sell the car b/c it just isn't worth it

light on the gas, find someone with a tuner and have them mess with your maf, and i also did a little with the timing, basic things like make shure your car is aligned, tire press, and the speed your driving at

Intake, dp, make sure your plugs & 02 are good...I think 22 is possible with that and a good tune, but I don't really have any experience yet. Someone else chime in and confirm or correct me.

Not to mention, take unneeded weight out of your car, use cruise control when possible, avoid excessive idling, properly inflate tires, don't drive aggressively, and don't drive insanely fast down the freeway - your car needs more power the faster it goes.

Of course, you can also tail-gate an 18-wheeler...mythbusters proved that saves gas mileage.

I have actually used that. Not tailgating them, of course, but staying a couple car lengths back still makes a difference.

I did two things a couple weekends ago that really made a difference. I am averaging 26 mpg. I can't tell you which thing made a bigger difference, I have no clue. (1997 GTP)

1) Changed a bad front wheel bearing.

2) Broke my MAF.

Let me explain- I unscrewed the MAF module and pulled it out. It was perfectly clean, so I didn't do anything to it. But in the process of doing that I broke the bottom half of the little plastic housing that surrounds the MAF elements. I know I did, because the next day I was pulling out onto the busy street and the car instantly died. Rolled into a gas station and did some troubleshooting. The little plastic piece had spun around in the hole the MAF lives in, blocking all airflow. So I fished that piece out and carefully put the MAF back in without it.

After that day, we're talking a 3-5 MPG improvement. And the engine *seems* to run a little quieter. Combined with the new wheel bearing NOT rumbling on the highway, it's like a whole new car.

(Another thing I've done for MPG is keep the tires inflated to their maximum rating. Hasn't caused any bad tire wear. If anything it's improved it.)

I think the only thing that max tire pressure does is you feel the bumps a lot more...

you do feel bumps more, but your tire print will be slimmer as well, so you should lose less energy to friction at a cruise. I wouldn't fill it up to max because your tires are going to heat up, increasing tire pressure over what it was while cold. Just run the recommended level unless you're at the track.

Tires have a max "while cold" rating on the sidewall. Usually around 44psi. Even if you run that, you will wear out the center of your tread before too long.

I usually run 2-4psi over factory recommendations. Also, the required pressure changes drastically with different rim and tire sizes. Larger rims usually mean higher pressure.

32 around town town, 35 on the highway...lol... but thats not the grand prix.


The GP gets about 18-19 around town and 31 highway.

31HWY with the gp thats good i got my max over the weekend of 25mpg best ever

Its all in the tune, man. Its all in the tune

Before you crash, go down to 32-35. Your tires are the first part of your suspension. With no rebound ability because they are pressurized so high, they lose contact with the road. I mean they actually bounce off the road with each bump and expansion joint. Read here for expert info:

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=1

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=3¤tpage=1

I'm confused. I would think the average of the last 500 miles driven would be pretty good.

My DIC is actually pretty accurate.

The thing is it's based more on fuel flow vs speed. If you reset it do your normal drive by the end of the tank it'll be pretty close.

Question how good are the driver information center on gtp? Everywhere i drive which is all highway i get around 28 and in city around 23 ? maybe cause im not that modded yet?

I get that and I am modded.

I thought you said you were running 13's? That to me means you're modded.

Long story about that... previous owner said it ran 13s, but the engine bay is completely stock.

Can anyone explain why my mileage dropped from 25.5mpg to 22.5mpg when I shifted to 93 octane? The car drives great but I don't think I'm driving it any harder than I did before. It's a combined highway/city loop about 100 miles long a day and rarely varies.

Is your car supercharged? If not, no reason to run 93 Octane, in fact 91 is the norm.

Some refineries use 10% alcohol to raise the octane rating. Alcohol has less BTUs per gallon so it takes more to get the power out of it.

I get around 22-24 back and forth to work and some of that commute is highway...On a trip running between 70-75 I usually get 27...if I slow down to 65 on cruise it will do 30. I dont think thats bad considering the GT has the highest numerical gear ratio.

ha im getting 24 city right now since my fuel pump is shot and i cant bring the engine above 3200rpms so i went from 17 city to 24...i guess thats the only good thing about a dying fuel pump

72chevman,
Yup, my car is a GTP. Your comment about using alcohol to raise octane makes sense. I use Shell exclusively and their ratings are 87, 89 and 93 in the Baltimore/DC area where I live.

Congrats to all who have great gas mileage. I have not checked in quite a while but will be doing so shortly. Gas just hit $3.95 here yesterday. I think I might trade the GPGT in for a gasoline tanker truck. I wonder if the fuel companies are hiring? I thought we were winning the war on TERROR. Hmmmm... now who is the bad guy? Sorry, just had vent alittle and I don't mean my tank.LOL *humor*

I am wrong about my gas miles! The reason i was getting that kinda miles is cause i almost reset it everytime. I was reading another deal and hercman was saying dont mes with it and by the end of your tank it should be pretty close to what your getting and im getting around 19.8 or so but if i get on it it drops to about 14 but that was my mistake.