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gas mileage

Update on my 2000 GT coup, I averaged 25.5 from Marion, IL to Pittsburgh, PA. I removed my cold air intake before returning and averaged 27 on the return trip. Also found my DIC to be accurate because I took the total miles on the gauge and divided by my gas used. Total mileage was 350 for the tank full. On the other hand, my 2002 GTP coup averages around 31 MPG and over 450 miles on a tank full. I don't gun it, averaging about 70-72 MPH for the trip on cruise control.
 


GT's have different gearing so the rpms are higher at 70-72 than a GTP.

Using CC sometimes can reduce mpgs as it is always trying to maintain a certain speed so the throttle % is always changing, but otherwise that mileage is okay for the size car.
 
I never knew the GT has different gearing, thought it was always the same engine and transmission. I am pleasantly surprised by my GTP getting 31 MPG but allot of that depends on road conditions, weather, and such. I usually only take it out during nice weather and the only big mileage test I did was when I drove it from Washington DC to Marion IL and it got 28.5 MPG but that was snowy weather, bad roads and the air filter was clogged. That is when I first purchased it. When I drive to Paducah KY from Marion which is 50 miles each way, I average 31 MPG
 
I never realized what a profound difference winter/summer driving has. During the winter, if i got 23mpg I thought i was doing pretty good. Since its warmed up Ive taken a few runs where the trip average is between 33 and 36. I know some of it has to do with not idling near as much, but that doesnt explain all of it.

During the winter, my trip to church (32mi) would average 21-24 in rolling terrain at speeds between 35 and 55, last sunday my trip average was 33, today it was 29, but i had the windows down.
 
Summer gas maybe cruising a little more enjoying the weather versus getting there as fast as possible because its freezing outside. Also compressor isn't running since you don't have defrost running all the time like in winter.
 


My gas mileage in the summer is so much better than winter. I took the red Grand Prix out and took a little trip with it raining and cold and gas mileage plummeted to 25MPG and averaging around 60. That was on the back roads which go up and down, lol.
 
I do all city driving and short trips on my 3.8 N/A (worst case scenario for gas mileage). I got about 13.8 MPG in the winter, and now I'm getting 16.2-16.5 MPG since it's gotten warmer (my driving habits haven't changed a bit, I'm always light on the pedal).

The gas light had just come on at 236 all city miles to the tank, and I was able to put in 14.5 gallons of gas. I used gumout's fuel system cleaner on today's fillup. Let's see if that helps any, it may get confused with warmer weather giving me better gas mileage, though.
 
My red GT does better in city but was doing worse than yours then I replaced the temperature sensor ACDelco 213-243 which helped allot. I also cleaned the MAF sensor with contact cleaner that is safe for plastic.
02NavyBlue said:
I do all city driving and short trips on my 3.8 N/A (worst case scenario for gas mileage). I got about 13.8 MPG in the winter, and now I'm getting 16.2-16.5 MPG since it's gotten warmer (my driving habits haven't changed a bit, I'm always light on the pedal).

The gas light had just come on at 236 all city miles to the tank, and I was able to put in 14.5 gallons of gas. I used gumout's fuel system cleaner on today's fillup. Let's see if that helps any, it may get confused with warmer weather giving me better gas mileage, though.
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I'm on a trip right now from Muskegon, Mi to Hammond, La. just installed a pair of Aeroforce Interceptors, and between Muskegon to Marston, Mo I averaged between 32-33 mpg. Main mods are a Wizard air intake, PLOG, AC delete for now, and 3" catted down pipe. Haven't had time to install the HV3 yet.
 


Just got my car on the road after the new build. I do about 80% highway. The DIC reads 32 mpg for now. Before the build, I was getting 27-28.
 
I have 2001 GP GT so 3.8L NA. Currently getting 24.5 MPG which is up from 23.1 i was getting before I installed K&N Air Intake and Throttle Body Spacer. Car has 217,000 kilometers (135,000 miles) on it and I have just started running one tank of Premium every (3rd) month to see if that makes any difference. Daily Driver 50-50 City and Highway, I rarely let get empty, but I have got 320 miles on a tank with some still in the tank (light was just coming on when I pulled into the gas station).
 
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Just filled my tank, gas was $4.01 for regular. I drive 100% city and short trips, and am getting 17.3 MPG with a light foot, most of the time.
 


Just took the GTP out last weekend on a nice day to Paducah which is a 100 mile round trip and still averaged 31.5 MPG so I would have to say its no fluke. My GT still gets around 27.5 to 28 MPG.
 
^^^^^hahaha u 3.8 people and ur good gas mileage...that blows u get that good.
I love my average 23 hwy why would anyone want any higher than that
 
With the price of gas I think everyone is doing what they can do to get better gas mileage. When gas was cheaper, I never looked at the gas mileage
 
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