# Mpg? Wtf?



## 05_HUMBLER (Jul 18, 2005)

My wife gives me sh*t every time I have to fill up. She drives a CTS and wonders why I have to fill up more often than her? Anyway I was trying to get the best possible MPG and so far I can only get 16MPG? It's city driving mostly, some highway. WTF Is it me or the car. I have got better than this but latley no way. A couple of tanks ago I checked the computer and I got an average of 11MPG!!:willy: I think I have a heavy foot, but dam, for the past couple of day I have been driving like a 90 year old and still I can only get 16!!! What say you?


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## johnebgoode (Oct 4, 2005)

If I was getting 16 mpg I would raise the flag and sing the Star Spangled Banner. All I do is stop and go driving and I'm gettin 10 mpg.


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## b_a_betterperson (Feb 16, 2005)

If you're in stop and go conditions a lot, you'll never get decent mileage. If you drive an automatic -- same deal.

However, if you're driving an M6 and are getting that kind of mileage -- you either have a heavy foot, a hole in your gas tank, or your wife is siphoning gas out of your car to top hers off.

The owner's manual contains the ideal shift points for the GTO -- from an economy standpoint. For the '04, they are:

First Gear: 0 - 15
Second: 16 - 22
Third: 23-30
Fourth: 31-40
Fifth: 41-50
Sixth: 51 and up

Real fun, huh? Those shift points are something like 1500 RPM -- so that will give you an idea of just how limiting they are. You've 5.7 to 6.0 litres of space to fill -- so it's going to consume a lot of gas if you get any RPMs going at all.

Beyond the shift points, if you have a manual, you can do stuff like coast downhill or coast up to stoplights, etc. But nothing raises your overall MPG like a nice freeway trip. In my '04, I'm able to get around 17 MPG city -- but that's using every trick in the book.

Also, depending on where you live -- the formulation of "winter gas" may be such that your mileage gets taken down a couple of points.


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## s2gordon (Dec 15, 2005)

The best I can get in my 05 M6 here in traffic from altamonte springs to orlando is 13-14 mpg and that's doing the 2,4,6 shift and keeping the rmps below 2K. If I hammer it then i get around 11 mpg. My wife gets 13mpg in her Navigator.


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## GTODEALER (Jan 7, 2005)

Oddly enough I've found that shifting around 2800-3000 when I had mine (stock) netted the best economy (18 mpg), Danielle (the current owner) is consistently seeing 19.5 mpg with medium amounts of stop and go traffic, the mpg is there your just shifting in the wrong rpm (which I understand that shifting at a higher rpm looks like you'll be using more fuel, but, trust me and try it).:cheers


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## 05_HUMBLER (Jul 18, 2005)

I guess I'm not the only one! Thanks for your input. I will check the manual for the shift points for fuel economy. That's what I thought as well DEALER. The way I understood it was dont shift too soon, otherwise you will bog the motor and it will suck more fuel rather than shift at 3 grand. I'll give it a shot. Thanks again.:cool


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## GTODEALER (Jan 7, 2005)

05_HUMBLER said:


> I guess I'm not the only one! Thanks for your input. I will check the manual for the shift points for fuel economy. That's what I thought as well DEALER. The way I understood it was dont shift too soon, otherwise you will bog the motor and it will suck more fuel rather than shift at 3 grand. I'll give it a shot. Thanks again.:cool


No problem, hope it helps!:cheers


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## dealernut (Oct 22, 2005)

GTODEALER said:


> Oddly enough I've found that shifting around 2800-3000 when I had mine (stock) netted the best economy (18 mpg), Danielle (the current owner) is consistently seeing 19.5 mpg with medium amounts of stop and go traffic, the mpg is there your just shifting in the wrong rpm (which I understand that shifting at a higher rpm looks like you'll be using more fuel, but, trust me and try it).:cheers



:agree 

Shifting around 2500 for me nets the largest gains.


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## s2gordon (Dec 15, 2005)

Hmm.. i'll try that with a new tank of Gas. This is the first Manual V8 i've had. All my other manuals were 4cyl so shifting at 2K rpm was better for fuel economy.


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## toolman (Jan 10, 2005)

I have an 04 and I drive it hard and get roughly 16.5 mixed between city and highway 50/50. If I loaf it around I get 19-20. I have never gotten below 15 and this was in the winter letting it idle for 10-15 minutes before taking off.


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## LYNMUP (Nov 26, 2005)

We had an 05 Limited Escape (200HP V6) and we were lucky to see 12 MPG. We average 16 in the GOAT and I drive under varied conditions. Lot of hard take-offs folowed by smooth cruising afterwards.


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## BuffGTO (Dec 29, 2005)

I average 12-13......:seeya:


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## GTODEALER (Jan 7, 2005)

I average 21mpg (in Radio....), around 19 mpg when I'm "in it" all the time.


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## 05_HUMBLER (Jul 18, 2005)

I feel a little bit better about 16mpg (I guess:confused ) I will try 2500 rpm shifts and see how that works. How can they say 17mpg city and 25 highway when we have to try so hard just to get 16mpg? oh well I'm not going to loose any sleep over it. :seeya: Thanks


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## gclcpa (Jan 9, 2005)

*Gas mileage*

I get right around 20 mpg on average in my 2004 A-4, in mixed driving. I drive in a lot of traffic at the beginning and end of my 80 mile round trip commute every day. The middle of my commute is through rural areas, where I average around 50 mph. I usually use a relatively light throttle, and run full throttle a few times during each day. My overall average speed is usually in the low 30's. The trip computer mpg has gotten more accurate over time, and usually I am running slightly better than the computer. I have owned my car since 1/22/05 (15 miles on the odometer when purchased), and I now have about 23,500 miles. 

By the way, I still have my original stock tires, but I do not like them. They make a lot of road noise, and sound like they are out of round. The car also tends to follow seams in the roadways very badly. Would that be tires or a suspension characteristic? I am thinking of getting Toyo Proxes 4 tires when I have to replace the stock tires. Anyone have any experience with these tires?


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## dizz81 (Jan 29, 2006)

My shifts consist of 2k-4k and cruising not in 6th but 5th under 65 mph and then shifting above that.. I run into alot of traffic lights probably 1 every 1/4 mile and farther apart.. I usually run about 300 to 325 miles to a tank.. depending on if I do any racing.. if I do some racing I usually get about 280.. nothing ever lower so far.. and I got 10k on the clock..


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## fat nick (Aug 21, 2005)

dizz81 said:


> My shifts consist of 2k-4k and cruising not in 6th but 5th under 65 mph and then shifting above that.. I run into alot of traffic lights probably 1 every 1/4 mile and farther apart.. I usually run about 300 to 325 miles to a tank.. depending on if I do any racing.. if I do some racing I usually get about 280.. nothing ever lower so far.. and I got 10k on the clock..


You have 10k miles already!!!!!!!! How, you have only had that car a few months.


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## C5ORGTO (Dec 30, 2004)

LOL. Sorry, I'm just ROTFLMAO. The first couple months, I got 11.9, or 12.5mpg. I worked my way up to 13.5mpg, and I'm proud of it. If I slow down, I can get 14mpg, but what is the point. They do get better mpg as they break in. After 5,000 miles mine got better. I've got an 04 with 7,200 miles. I'm hoping after 10,000 I'll get 20mpg. LOL..... :lol:


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## HotRodGuy (Jan 9, 2006)

I do about even freeway and city miles, about 400 a week w/ a good amoutn of stop and go traffic as well. I'm getting roughly 18 mpg


I'm doing a road trip soon, I wouldn't be suprised if I saw 25+, i've seen 30+ in my dads vette :willy:


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## fergyflyer (Apr 18, 2005)

I usually got 16-17 around town. I did the same as GTODealer and would run her up to 2500-2700 to shift. I found by using lower shift points I got worse. I also skipped gears a good bit. 1-3-5 or 2-4-6. 
Out on the highway I would get between 23 and 24 with an occasional 25 in there. 

Just to make you sick, in the C6 I've been getting about 20-20.5 around town and had one trip to Ft. Lauderdale that I got 28 off of at 78 with the air on. I also had a trip at 82 that got 27.5 and 72 with the air off that got 32.5. The trip computer has always been with-in a tenth of what I get by checking gallons pumped versus miles. Same LS2 just 600 lbs less weight, better aerodynamics and a great 6 speed auto.

Then to make you feel better, the 6cyl Dakota gets 18-19 around town and 18-19 on the highway. Every once in a while I'l see 20.


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## MeanGoat (Jan 4, 2006)

My '05 M6 has definitely gotten better in the past few months.

I've got about 12K on it so far and I'm starting to see about 240 miles per tank in stop and go traffic. About a 12 mile, 15 minute commute on the weekends but same distance and 45 minutes during the week. Trip computer says over 15mpg, but I don't believe those confounded doo-hickeys.

Oh yeah, _I get on it._ I enjoy unnecessarily quick take-offs and cruising 6 car lengths in front of the pack if I'm first in line at a light. When cruising, I shift at 2800-3500 on average find it the optimum shift point for fuel consumption.

I get about 24 mpg when going from Tampa to Miami which is pretty well 6th gear at 85 mph the whole way. With spurts of 130-140 while I'm in Alligator Alley.


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## NT91 (Aug 30, 2005)

I get between 16.5-17.5 in my Auto 05 GTO.


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## noz34me (Dec 15, 2005)

Car computer says I'm averaging 21.3 mpg. I accelerate briskly from stops, but not "pedal to the metal" except on Interstate on ramps. Love those things.

I also drive 38 miles each way to work. 

Right at 938 miles on my '05 6M.


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## noz34me (Dec 15, 2005)

noz34me said:


> Car computer says I'm averaging 21.3 mpg. I accelerate briskly from stops, but not "pedal to the metal" except on Interstate on ramps. Love those things.
> 
> I also drive 38 miles each way to work.
> 
> Right at 938 miles on my '05 6M.


Guess I should also mention my car computer always says I've used 1/2 gallon more than I've used when I check at fill up time.


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## LS2 - Light SpeedX2 (Nov 10, 2005)

I have 05 m6. I was getting about 20-21 until I put in the magnaflow catback and K&N CAI over the past 2 weeks. Now I am getting about 12-15. Of course, it's my own fault. I love the sound of the new exhaust and the cai sounds like it is going to suck the paint off of my inner fender. Give me a couple of weeks and my testosterone should com back down to normal levels. I will have to post the video of mine without pipes. Awsome.


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## 05_HUMBLER (Jul 18, 2005)

> I have 05 m6. I was getting about 20-21 until I put in the magnaflow catback and K&N CAI over the past 2 weeks. Now I am getting about 12-15. Of course, it's my own fault. I love the sound of the new exhaust and the cai sounds like it is going to suck the paint off of my inner fender. Give me a couple of weeks and my testosterone should com back down to normal levels. I will have to post the video of mine without pipes. Awsome.


:agree Yeah I know what you mean. When I got my LPE Cai for a couple of weeks after I was "in it" everywhere I went! Love that sound!!!!

I found a different way to go to and from work (less traffic lights) and I have been using 2500-2800 shifts and I've seen my milage go up to 18-19 MPG. Thanks Guy's Beers are on me! :cheers


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## baron_iv (Nov 17, 2005)

On my trip to vegas last month, I got 24.7 mpg averaged over the entire trip, which included everything from 3 hours in stop/go traffic in Las Vegas to 90-100mph highway traffic, to the occasional race stoplight to stoplight and up to 140 mph on the highway. That was one hell of a run-on sentence.
Anyway, I have the M6 tranny. I had a supercharged 6-cylinder truck which didn't get that good of mileage over that same trip. The truck DID perform much better in the mountains with the supercharger though. Above 4500 feet or so, the goat felt more like a three-toed sloth. I was really glad to get back down to normal altitude where the car ran like a bat outta hell.


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## Justice (Oct 9, 2005)

I'm getting 18.9 average. Of course I actually don't mind the 1-4 skipshift that everyone else hates. For most of my casual driving, it usually have a 1-4-6 upshift pattern. I think 5th is the most unused gear on my car.


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## 05_HUMBLER (Jul 18, 2005)

:agree I also like the "skip shift" 1-4-6 is what I do most. We _have_ a 5th gear????:lol:


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## jacobyb (Jan 2, 2006)

I used to have a link to a study that was done by BMW back in 1980 during the fuel crisis. They found that accelerating at an "above average" pace netted better MPG numbers then leisurely acceleration. 

The reasoning behind it is that an internal combustion engine works at its most efficient when it is at a constant speed/rpm. That is why HWY MPG is better than stop and go. If you are in city traffic and you are accelerating slowly, you are constantly in an acceleration mode and never get to the more efficient constant speed.


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## UdnUdnGTO (Jan 30, 2006)

:agree There are so many factors in gas mileage. What kind of gas? What octane. I had a 350Z that ran best on Shell. This GTO loves BP (Amoco). What type of oil? If you got under 30,000 miles on your car, go to a 0w30 or 0w40 synthetic. Amsoil has a real good 0w30. I have it in my GTO. I enjoy my gas mileage by turning the computer to the digital speedometer. Ha. I would guess I get about 50 mpg on the fun-o-meter. Now on the computer probably around 20 overall. As for me my mpg comes form the fun-o-meter.


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## C5ORGTO (Dec 30, 2004)

HotRodGuy said:


> I do about even freeway and city miles, about 400 a week w/ a good amoutn of stop and go traffic as well. I'm getting roughly 18 mpg
> 
> 
> I'm doing a road trip soon, I wouldn't be suprised if I saw 25+, i've seen 30+ in my dads vette :willy:


I traded a Vette in on a GTO, and the Vette got 30mpg all the way to Chicago. 200 Miles. The GTO got 22 or 23 on a trip to Illinois, 225 miles. The extra weight kills this car. The computer is saying 12.9mpg today at lunch.


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## baron_iv (Nov 17, 2005)

jacobyb said:


> I used to have a link to a study that was done by BMW back in 1980 during the fuel crisis. They found that accelerating at an "above average" pace netted better MPG numbers then leisurely acceleration.
> 
> The reasoning behind it is that an internal combustion engine works at its most efficient when it is at a constant speed/rpm. That is why HWY MPG is better than stop and go. If you are in city traffic and you are accelerating slowly, you are constantly in an acceleration mode and never get to the more efficient constant speed.


I agree with that 100%. I always thought it was because I spent more time coasting once I got up to (or above) speed, which sent the average up to 99.9 on the instant mileage, which was factored into those few seconds of 7-9 mpg. However, it does make sense to me to get up to speed as quickly as possible since you're having to fill those cylinders fewer times. Plus, it's just a helluva lot more fun to get up to speed as fast as possible.


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## LynnF1 (Nov 21, 2005)

05 A4 here - I mostly commute (rush hour, some stop and go), with the occasional SEG-inducer thrown in... 18.5-7 on the computer most of the time.


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## PONTIACSTYL (Feb 21, 2006)

From clermont to orlando my wife averages about 19 in stop and go traffic. we have the 6 - speed


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## Ironmancan (Feb 11, 2006)

Average MPG from Tampa to Jacksonville Fl was 22.5 Mpg. All highway between 70-80 MPH.


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## rrathea (Dec 1, 2005)

Tampa to Orlando and back - 26.5 - running 70 without a/c.
Avg 15 City

Supercharger is being installed this week. Something makes me think those numbers are in the past...


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## Subdriver (Dec 28, 2004)

jacobyb said:


> I used to have a link to a study that was done by BMW back in 1980 during the fuel crisis. They found that accelerating at an "above average" pace netted better MPG numbers then leisurely acceleration.
> 
> The reasoning behind it is that an internal combustion engine works at its most efficient when it is at a constant speed/rpm. That is why HWY MPG is better than stop and go. If you are in city traffic and you are accelerating slowly, you are constantly in an acceleration mode and never get to the more efficient constant speed.


I think you are a little off in your reasoning. 

The reason hwy mileage is better than stop and go mileage is because every time you stop the car you have lost all the kinetic energy into heat energy disappated by the brakes. To get the car back up to speed, the engine must expend all that energy again. That is why hybrid's get such good gas mileage. When they slow down they don't lose that kinetic energy to heat, they transfer it to electrical energy stored in the battery, which is then used to accelerate the car back up to speed. 

But, every internal combustion engine will have its most efficient operating point and I think what the study implied is that this point is not at low rpm cruising condition, it is at a higher rpm acceleration point. 

The point about about the fluids in the engine, tranny and diff should be noted. AMSOIL did a study a while ago in a fleet of diesel trucks showing the mileage improved 8.2% when shifting engine, tranny and diff fluids to AMSOIL.
Diesel Fleet Mileage Test
:cheers


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## 84racebird (Jan 4, 2005)

I have been driving my '04 6 speed to work all this week and some of last. I have a 35 mile commute, mostly tollway with some stop and go because of construction. I have been getting gas mileage in the low 20's. Over the last 1000 miles I have 20.6 mpg on the display. I have discovered the magic of 6th gear. It gives me a nice 30 mph roll and mileage in the 30's on the instantaneous mileage display without touching the gas pedal. I have even started driving around town in 6th. I know it sounds crazy, but I'm use to getting 32mpg all around every tank with my Saturn.


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## Don (Sep 20, 2004)

In town I get about 15mpg, Iconsistantly get my best mpg at about 85mph which in 6th gear is over 2200rpm. I drove from Aplina Mi. to S. Bend In. at an average indicated speed of 78.3 and got 28.2 mpg. The bearing in this car makes for good economy at high speeds which makes sense if you live in the outback down under.


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## Don (Sep 20, 2004)

Make that "The Gearing"


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