Why are my mpg's so low
01-06-2011 | 03:33 PM
#1
Thread Starter
Instructor
Joined: Nov 2010
Posts: 228
Likes: 2
From: Miami
Why are my mpg's so low
i wondering why my mpg's are so low it showing 15 since i got the car, also i want to know why does it show two mpg is it one for the street and one highway ine says 15mpg and 22mpg
01-06-2011 | 03:39 PM
#3
It's your driving style. You must be having fun with your car and/or do a lot of city driving.
I got bored this week and wanted to see how high I can get my average MPG so all week commuting to work, I tried staying between 55-65mph and ended up at 30MPG. Normal driving I'm at 23-24MPG. If I play a lot, it's around 18-19MPG. I have about a 70 mile round trip commute daily.
Not sure where you see two MPG. Are you sure one isn't MPH?
I got bored this week and wanted to see how high I can get my average MPG so all week commuting to work, I tried staying between 55-65mph and ended up at 30MPG. Normal driving I'm at 23-24MPG. If I play a lot, it's around 18-19MPG. I have about a 70 mile round trip commute daily.
Not sure where you see two MPG. Are you sure one isn't MPH?
Trending Topics
01-06-2011 | 03:56 PM
#11
Thread Starter
Instructor
Joined: Nov 2010
Posts: 228
Likes: 2
From: Miami
01-06-2011 | 04:57 PM
#13
01-06-2011 | 05:08 PM
#15
Instructor
Joined: Oct 2010
Posts: 106
Likes: 5
Check your air filter and spark plugs. I put on mostly city miles and I average 21. Like they said it could be your driving habits. Do you go straight from gas to break, take off quick, drive short distances??? Short distances in cold weather will cause for low miles too. I get better milage in the summer months.
01-06-2011 | 07:07 PM
#19
Keep Right Except to Pass
Joined: Aug 2004
Posts: 2,409
Likes: 45
From: Kingstowne, VA
I tend to get between 18 to 20 mpg in city driving (6MT, DC area) but 30+ mpg on the highway. Last weekend we went to Pittsburgh for the NHL Winter Classic and I averaged 29 mpg for the tank I used on the way up and part of the way back. Had I not done some city driving around Pittsburgh I would have been over 30 mpg. Mileage on the way home was similar but not quite as good due to heavier traffic and two backups (some damn fool Penguin fan got a flat in the Allegheny Mountain Tunnel.....). I did use the cruise control quite a bit in both directions, which always helps as well.
Essentially, the TL absolutely LOVES the highway, especially if you have the 6MT and can leave it in 6th for a long time.
Essentially, the TL absolutely LOVES the highway, especially if you have the 6MT and can leave it in 6th for a long time.
01-06-2011 | 07:10 PM
#20
Check your air filter and spark plugs. I put on mostly city miles and I average 21. Like they said it could be your driving habits. Do you go straight from gas to break, take off quick, drive short distances??? Short distances in cold weather will cause for low miles too. I get better milage in the summer months.
the MID calculates average MPG according to average MPH.
if you reset the MID you're not getting a true calculation.
We dont have an instantaneous mpg gauge.
01-06-2011 | 07:23 PM
#24
01-06-2011 | 08:30 PM
#27
Of course if you reset it while you're cruising at 60 down a hill you're going to get 99 MPG. No one is saying reset it and after 5 seconds that is an accurate MPG calculation. Reset it, and drive it for 100 miles, and you'll have an accurate average MPG. I have found the MID to be within 1 MPG of manual calculation.
01-06-2011 | 09:16 PM
#29
Drifting
Joined: May 2006
Posts: 2,499
Likes: 221
From: Carlsbad, CA
The gas mileage threads do get old, but lets liven things up?
Here's a quick ballpark method that doesn't even require a calculator- just answering a few simple questions:
1. Do you reset your MID each tank and fill up the tank each time? If so continue on- otherwise try this one tip before complaining about gas mileage because you really don't have much data to go by and need enlightenment.
2. Is your average MPH (calculated by the MID in addition to MPG that everyone always quotes) < 30 MPH ?
If so, use 20 MPG as your baseline and then subtract .5 MPG for every one MPH below 30 MPH.
If higher, use 20 MPG as your baseline and then add .5 MPG for every one MPH above 30 MPH up to 65mph. Speeds higher than 65 are capped at 35MPG and then decrement by .25 MPG for every 1mph higher.
3. Are you running with Oxygenated fuel during parts of the year for smog reasons (e.g. California during the winter months)? If so subtract one MPG from question #2
4. Are your tires under-inflated? If so subtract 1 MPG from your question #3 answer if below 30 MPH or 3 MPG if answer #2 is > 50 MPH
5. Are you running with high performance tires? If so subtract 1 MPG for < 30 MPH average speeds and 2 MPG for > 30 MPG speeds
While not scientific, I bet answering these questions will get you within 1-3MPG of actual mileage. I'm using my own data as a benchmark which involves a spirited, urban, and mostly flat commute. My actual MPG is a hair higher than the formula calculates in some cases and dead on in others. It seems withing 1MPG of actual in both urban and highway commutes though.
Hopefully others will try this out and comment- we might have to adjust the factors more based on terrain- I was trying to keep this very simple with no calculator needed.
Give it a shot
Here's a quick ballpark method that doesn't even require a calculator- just answering a few simple questions:
1. Do you reset your MID each tank and fill up the tank each time? If so continue on- otherwise try this one tip before complaining about gas mileage because you really don't have much data to go by and need enlightenment.
2. Is your average MPH (calculated by the MID in addition to MPG that everyone always quotes) < 30 MPH ?
If so, use 20 MPG as your baseline and then subtract .5 MPG for every one MPH below 30 MPH.
If higher, use 20 MPG as your baseline and then add .5 MPG for every one MPH above 30 MPH up to 65mph. Speeds higher than 65 are capped at 35MPG and then decrement by .25 MPG for every 1mph higher.
3. Are you running with Oxygenated fuel during parts of the year for smog reasons (e.g. California during the winter months)? If so subtract one MPG from question #2
4. Are your tires under-inflated? If so subtract 1 MPG from your question #3 answer if below 30 MPH or 3 MPG if answer #2 is > 50 MPH
5. Are you running with high performance tires? If so subtract 1 MPG for < 30 MPH average speeds and 2 MPG for > 30 MPG speeds
While not scientific, I bet answering these questions will get you within 1-3MPG of actual mileage. I'm using my own data as a benchmark which involves a spirited, urban, and mostly flat commute. My actual MPG is a hair higher than the formula calculates in some cases and dead on in others. It seems withing 1MPG of actual in both urban and highway commutes though.
Hopefully others will try this out and comment- we might have to adjust the factors more based on terrain- I was trying to keep this very simple with no calculator needed.
Give it a shot
01-06-2011 | 09:16 PM
#30
Racer
Joined: Jul 2010
Posts: 465
Likes: 6
From: Chicago, IL
My MID is very accurate. Last time I checked it read 18 MPG and the calculation at the pump was 18.4.
It has to be a more sophisticated system than just giving an average MPG based only on the average MPH otherwise we would all be getting the same MPG at an average of 19 MPH. I've heard of some people getting as low as 13 MPG at that when I usually get about 20-22 MPG.
It has to be a more sophisticated system than just giving an average MPG based only on the average MPH otherwise we would all be getting the same MPG at an average of 19 MPH. I've heard of some people getting as low as 13 MPG at that when I usually get about 20-22 MPG.
01-06-2011 | 09:24 PM
#31
Drifting
Joined: May 2006
Posts: 2,499
Likes: 221
From: Carlsbad, CA
ssdale- you're absolutely right about the MID being accurate. MPH is huge because low values usually mean lots of idle time or stop/starts which kills gas mileage. Remember when you're in a Drive-thru or traffic light idling you are getting ZERO MPG and consuming fuel. I see people all the time idling their cars in parking lots talking on the cell phone- I'm sure they have sucky mileage if they do that all the time. It looks like the MID does a very simple calculation for MPH: Total Miles / Total Time.
All this formula does is predict what the mileage would be based on MPH. I still find it very accurate as this case in point- off by 1.5 MPG in the OP's case.
All this formula does is predict what the mileage would be based on MPH. I still find it very accurate as this case in point- off by 1.5 MPG in the OP's case.
01-06-2011 | 11:25 PM
#32
I would say so....lol I usually average 28-34 mpg on a full tank in my CL
Er I mean 300-400 miles on a tank maybe more if its all highway.
Right now I usually get up to 250-300 before I hit a quarter of a tank .
Er I mean 300-400 miles on a tank maybe more if its all highway.
Right now I usually get up to 250-300 before I hit a quarter of a tank .
Last edited by OperationDarkie; 01-06-2011 at 11:34 PM.
01-07-2011 | 12:08 AM
#34
Instructor
Joined: Jan 2010
Posts: 119
Likes: 0
From: San Antonio, TX
damn i wish i got that! yah and this is commuting 40 miles round trip, mixed in with light driving in city.
01-07-2011 | 07:40 AM
#35
my mid is very accurate. Last time i checked it read 18 mpg and the calculation at the pump was 18.4.
it has to be a more sophisticated system than just giving an average mpg based only on the average mph otherwise we would all be getting the same mpg at an average of 19 mph. I've heard of some people getting as low as 13 mpg at that when i usually get about 20-22 mpg.
it has to be a more sophisticated system than just giving an average mpg based only on the average mph otherwise we would all be getting the same mpg at an average of 19 mph. I've heard of some people getting as low as 13 mpg at that when i usually get about 20-22 mpg.
ssdale- you're absolutely right about the mid being accurate. Mph is huge because low values usually mean lots of idle time or stop/starts which kills gas mileage. Remember when you're in a drive-thru or traffic light idling you are getting zero mpg and consuming fuel. I see people all the time idling their cars in parking lots talking on the cell phone- i'm sure they have sucky mileage if they do that all the time. It looks like the mid does a very simple calculation for mph: Total miles / total time.
All this formula does is predict what the mileage would be based on mph. i still find it very accurate as this case in point- off by 1.5 mpg in the op's case.
All this formula does is predict what the mileage would be based on mph. i still find it very accurate as this case in point- off by 1.5 mpg in the op's case.
OWNED.
01-07-2011 | 11:34 AM
#37
Dumbass. LoL. I didn't know 24yrs old still said that. 
I don't trust ONE person with ONE result. I prefer see multiple tests. Fill up at the same pump with the exact same volume of fuel. Drive the same exact mileage, over a period of say a month. Preferably in the same weather conditions. I'd say 4 weeks with 4 fill ups is an adequate test.
How much are you idling during a course of a tank of fuel?
Tire inflation has a huge impact on fuel economy.
I don't trust ONE person with ONE result. I prefer see multiple tests. Fill up at the same pump with the exact same volume of fuel. Drive the same exact mileage, over a period of say a month. Preferably in the same weather conditions. I'd say 4 weeks with 4 fill ups is an adequate test.
How much are you idling during a course of a tank of fuel?
Tire inflation has a huge impact on fuel economy.
01-07-2011 | 12:08 PM
#38
^ Isn't it enough to compare the MID MPG versus actual calculated MPG by filling up each time and resetting the trip meter? I do that every time, and the MID has always been within 1 MPG of the actual calculated value.
01-07-2011 | 01:29 PM
#40
The MID is very accurate. Probably +/- 1MPG. That's the general consensus on this forum.
OP - Reset your MID to get recent results, drive more conservatively, properly inflate your tires, and use premium fuel and you'll see your MPG increase. Also, like people have been saying, there is correlation between your MPG and MPH. The higher your average MPH is, the better your MPG will be.
Also, search is your friend.
OP - Reset your MID to get recent results, drive more conservatively, properly inflate your tires, and use premium fuel and you'll see your MPG increase. Also, like people have been saying, there is correlation between your MPG and MPH. The higher your average MPH is, the better your MPG will be.
Also, search is your friend.