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Getting less than 15mpg, what's wrong with my car.


CrazyDave_merged

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Is it the heat? the humidity? or my fat right foot? I don't know.

 

I only tromp on it a little, and I get just 14.8MPG.

I tromp on it a lot, I get 14.8MPG.

 

I use 93 octane, or 89 octane, I still get less than 15MPG.

 

I am getting less MPG now than when I first bought car. First tank was almost 16MPG.

 

All city driving. Is this normal?

 

I have read some posters getting way better mileage, I wonder if they are fibbing?

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Is it the heat? the humidity? or my fat right foot? I don't know.

 

I only tromp on it a little, and I get just 14.8MPG.

I tromp on it a lot, I get 14.8MPG.

 

I use 93 octane, or 89 octane, I still get less than 15MPG.

 

I am getting less MPG now than when I first bought car. First tank was almost 16MPG.

 

All city driving. Is this normal?

 

I have read some posters getting way better mileage, I wonder if they are fibbing?

 

Same here, 14 mpg in town. Got 20 mpg on the last tank of 93 octane (1/2 city, 1/2 hwy). You are braver than I if you burn low octane fuel. Have 1,350 miles on the Shelby.

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I opened up my maintenance program to get the numbers for you. I am averaging 15.85 MPG. My best tank was the first tank from Barstow-OC all freeway, 19.41 MPG. My worst was just recently and with no freeway that I remember, 12.84 MPG.

 

I was actually curious if the supercharger was helping on the freeway at all. Looking at Stumps numbers I guess not.

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Even "city" driving can be very variable; I can see you getting 14.8 if you only do a lot of stop, go and idleing.

 

My computer was reading 19.2 last time I looked. I have never seen below 18.7 on it. When I first bought it I got 27.2 on my trip home to CT from my NY dealer.

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From past experiences, I think you need more miles on your cars to get optimum gas mileage. A couple of reasons, one the newness has worn off and you're not going through the gears quite as hard(lead foot). Two, you need to have 5 to 7 thousand miles on your car for your motor to loosen up. I'm going to take a guess that Gary and Stump have 6-8 thousand miles on their cars, since they have had them quite a while, the newness has worn off. They seem to have the best gas mileage. Not so much lead foot. Well I don't know about Stump. LOL So maybe when people post their gas mileage they should also add how many miles are on the odometer. I know our gas mileage isn't that good because the driver(Sherri) likes to watch the boost gauge :D . She just loves second gear. I'm always telling her OK, enough. :blink:

Dave

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From past experiences, I think you need more miles on your cars to get optimum gas mileage. A couple of reasons, one the newness has worn off and you're not going through the gears quite as hard(lead foot). Two, you need to have 5 to 7 thousand miles on your car for your motor to loosen up. I'm going to take a guess that Gary and Stump have 6-8 thousand miles on their cars, since they have had them quite a while, the newness has worn off. They seem to have the best gas mileage. Not so much lead foot. Well I don't know about Stump. LOL So maybe when people post their gas mileage they should also add how many miles are on the odometer. I know our gas mileage isn't that good because the driver(Sherri) likes to watch the boost gauge :D . She just loves second gear. I'm always telling her OK, enough. :blink:

Dave

 

I have ~9000 miles but my mileage has been consistent since the day I launched off the dealers lot.

My SAI trip put down about 3400 of those miles.

Our Shelby has two speeds. Stop and can't stop....

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3650 miles, averaging 19.1 miles, city - highway split about even.....maybe a touch more highway.

(Maybe I just turn the city streets into a highway....oops! :lol: )...j/k!

 

Every year (around here) there seems to be some expose about gas being sold under the octane listed, so I found a good gas station and try to stick with it. Have gotten bad mileage on other cars when "suspect gas" was used.

Sorry if that was "captain obvious strikes again!" :huh:

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I average between 18.2 and 18.7 per tank...with a pretty good mix of highway and city driving. The highway trip I took (500 miles) I averaged 25 mpg.

 

I had one tank a few weeks ago that I only got about 17.5 mpg--but it was really, really hot here that week and the AC was blowing full steam all the time.

 

I've got 6100 miles on SGT 507 so far.

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I am noticing a pattern, and I wonder if there is anything to it?

Are the people who took entended trips (over 500-1000 miles) when their cars were very "new" getting better MPG in general now?

When I say "new" I mean, when the car was either first picked up or definately within the first 200 miles.

Some of us said, "I dont want to drive that distance until the car is broken in!", others said,

forgetaboutit

and drove it like they stole it (in another State) from day one.

Did that long trip break in the motor earlier or better or differently?

 

Like I said, there is probably nothing to it, but?

Maybe the low MPG's can post if they had a trip like that and the Higher MPG's can post too 2see if there is anything to this..........

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I am noticing a pattern, and I wonder if there is anything to it?

Are the people who took entended trips (over 500-1000 miles) when their cars were very "new" getting better MPG in general now?

When I say "new" I mean, when the car was either first picked up or definately within the first 200 miles.

Some of us said, "I dont want to drive that distance until the car is broken in!", others said,

forgetaboutit

and drove it like they stole it (in another State) from day one.

Did that long trip break in the motor earlier or better or differently?

 

Like I said, there is probably nothing to it, but?

Maybe the low MPG's can post if they had a trip like that and the Higher MPG's can post too 2see if there is anything to this..........

 

I drove mine about 450 miles from Wayne Morris Ford in Perry, GA to Wake Forest, NC. I stayed on US Highway 1 and off of I-95 the entire drive, and I only beat on it really hard once during the trip. Again, I am at about 21.5 mpg on 93 octane with mixed city/highway driving after nearly 2000 miles.

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I'm a city driver mostly, sit at traffic lights and such. I'm averaging around 14 to 15 mpg on the computer readout. I haven't done a check using actuals, though (total miles on the trip odo/total gas pumped). I also have only 1500 miles total and use premium gas (93).

I gave up on being all concerned about this stuff. Instead of trying to increase the MPG read-out I now try to increase the Avg MPH for each tank of gas.

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I am noticing a pattern, and I wonder if there is anything to it?

Are the people who took entended trips (over 500-1000 miles) when their cars were very "new" getting better MPG in general now?

When I say "new" I mean, when the car was either first picked up or definately within the first 200 miles.

Some of us said, "I dont want to drive that distance until the car is broken in!", others said,

forgetaboutit

and drove it like they stole it (in another State) from day one.

Did that long trip break in the motor earlier or better or differently?

 

Like I said, there is probably nothing to it, but?

Maybe the low MPG's can post if they had a trip like that and the Higher MPG's can post too 2see if there is anything to this..........

 

 

Bump....I thought this would be an interesting comparison & the concept had some merit....but apparently everyone would rather itchb about hood scoops & stripe issues! <_<

Fine then. :lol:

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Is it the heat? the humidity? or my fat right foot? I don't know.

 

I only tromp on it a little, and I get just 14.8MPG.

I tromp on it a lot, I get 14.8MPG.

 

I use 93 octane, or 89 octane, I still get less than 15MPG.

 

I am getting less MPG now than when I first bought car. First tank was almost 16MPG.

 

All city driving. Is this normal?

 

I have read some posters getting way better mileage, I wonder if they are fibbing?

 

 

I have a Shelby Paxton SC with a custom tune and I consistently get 26-27 MPG if I drive in 5th gear at ~55-65 MPH. I drove it without the SC for the first 3 months and was getting ~23-24 MPG under the same conditions. So there is some fuel efficiency with the SC under certain conditions.

 

There is two lane back road that I take to the beach and it is loaded with small town speed traps that forces me to watch my speed and that is when I get the great fuel mileage. I’ve checked it by filling the tank and dividing the miles per gallon and it verifies exactly what the computer says.

 

Now the problem is I don’t drive very often in 5th gear at 55-65 MPH. It’s a daily driver and the typical mileage is 14-15 MPG around town. Part of this is because I find it hard to resist stomping on it to feel the power of the SC kick in. Those 6K shifts are just too much fun.

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  • 2 weeks later...

I'm bummed.....about paying the Gas Guzzler Tax :( I realize they don't calculate it based on pure Hwy miles. Too bad. Took a recent jaunt Portland OR to Reno NV weekend before last for the Reno Air Races. Left Portland with about 600 miles on the odometer. Mostly back roads but not much high speed stuff. 540 miles later about 25 mpg according to the trip computer. On the way back, slightly longer 570 miles, average speed 65-75mph with the odd 3rd gear 80-100mph pass thrown in and trip computer said 27.9mpg with an average speed of 64mph for the 570 miles. Shelby now has about 1800 miles on it.

 

Oh ya, also got it out on the track for one short 30 minute session at Reno Fernley Raceway. Kind of a twisty course, mostly 2nd and 3rd gear, brief 4th gear. I wasn't pushing hard, that's for next spring at a track I know like PIR, but I was impressed. Car handled nice and flat, good turn in, brakes were fine (I have the stock brakes but with SAI brake ducts, stock wheels and tires for now....), easy to kick the tail out when needed or let it step out. It wasn't until about 1/2 way thru the session that I remembered to turn the TCS off. Somebody (Ford? SAI?) did a good job programming that! Lots of fun. By all reports will be even more fun with the Steeda LCAs and Coast aluminum driveshaft in the garage waiting for install and "testing" later this fall.

 

Todd

csm1638

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I think some of the 25mpg folks are either full of gas, or they are only driving hwy where it is cool.

 

Several have comparable mileage to mine. Down south here where it has been over 90 degrees for some time, and bumper-to-bumper city driving, all you get is 15mpg. I have not taken a hwy trip yet. Gas does not just leak through the engine. Each region will have unique conditions.

 

I also drive a 3.0 Acura (20mph city) and a 3.5 Sienna (17mpg city). All three cars can't be malfunctioning.

I should see improvement when winter comes.

 

Several sources say that the octane does not realy effect mileage. Just knock protection. I put in 87, got 15mpg. Put in 93, get 15mpg.

 

Not using trip computer, actually measuring and doing the math. Computer says 18mpg. It's full of gas!

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