WTF is up with my gas mileage?
#1
WTF is up with my gas mileage?
I got an 03 6 speed about 2 weeks ago with 21 mpg on the display, and it has gone down ever since. Tonight I got gas, and calculated it to be just over 15 mpg. I mean, I'm not the best at shifting yet, but I wouldn't think that it would have THAT great of an effect on it. On the display right now, it says 18.5 mpg... however, as I said before, I calculated it to be just over 15 when I filled up tonight. Why the huge discrepancy between those numbers? Am I calculating it wrong? My process: I reset my trip odometer everytime after I fill up. Then then next time I fill up, I take the number of miles I've driven, and divide it by the number of gallons it took to fill up the tank (Tonight I drove 204 miles and it took about 13.4 gallons to fill up). That's the right process to calculate it right? Why is my calculation so vastly different than the display on the car?
I do city driving, and I don't redline the car. For the most part, I take it easy, but I do occasionally take it up to about 4-5k to shift. Like I said, i'm just learning to drive a stick and my upshifts are kinda jerky, but gotdamn. Would it make that huge of a difference in MPG?
These numbers are very disappointing, because one of the reasons I justified the increase in cost of getting the new car would be the saving in gas mileage. But now, it's basically the same as my old 2001 auto. I'm quite upset. What the hell is going on?
I do city driving, and I don't redline the car. For the most part, I take it easy, but I do occasionally take it up to about 4-5k to shift. Like I said, i'm just learning to drive a stick and my upshifts are kinda jerky, but gotdamn. Would it make that huge of a difference in MPG?
These numbers are very disappointing, because one of the reasons I justified the increase in cost of getting the new car would be the saving in gas mileage. But now, it's basically the same as my old 2001 auto. I'm quite upset. What the hell is going on?
#5
I get the same, my computer usually tells me I'm 3 or 4 mpg higher than what it really is... My sparkplugs are shot (94K) and my Airfilter is dirty. I am putting those spacers from aaron on...So, I'll see what happens now.
#6
Put more air in your tires, about 5psi more than what Nissan recommends. Also, try skipping gears. Go from 1st-->3rd-->5th or 2nd-->4th-->6th. Keep the revs below 2K rpms when shifting. Always use 6th gear when cruising on the street or freeway.
#7
i always try to keep it in the highest gear possible when cruising.. i might try that skipping thing
#8
thats weird.. why the hell is that? my sparkplugs should be good.. im only at 49k.. so you get the same gas mileage as i do? is something wrong with our cars?
#9
Mileage will vary from car to car, how well its maintained, and driving style all effect it. As stated before, bumping tire pressure helps. I run my fronts at 40 psi and my rears at 38 psi. The EPA suggests getting up to cruising speed "quickly", then skip to the highest gear. I drive almost 40 miles each way to work and back...half highway, half city. My average mileage using premium fuel is around 25-27 mpg, and regular fuel usually runs around 21-23 mpg. I didn't think fuel grade would make a difference but I tested them both for 4 full tanks using actual mileage.
#11
Mine usually always stays around 26-28 mpg but I drive mostly all highway miles,and mine is auto at 42,000 miles.Def check tire pressure after each fillup and keep learning that manual stuff..lol...Could just be a combination of things as well as city driving.
#12
Are you driving far enough for the car to fully warm up? How bad is the traffic where you live? Spend a lot of time idling at lights?
Traffic lights blow goats here. Cross street traffic lights change for no reason, 10 PM at night and the lights still operate on a morning rush hour cycle. I swear, traffic engineers are the stupidist people on the planet. Just kills my gas mileage and my average speed this last fill-up was 32 mph...and about 20% of my driving was on the freeway and the rest on streets with speed limits of 35 mph or higher. I've been averaging around 19.5 mpg since I got my car in mostly city driving...in fact, this last tank was 19.5 on the dot (okay, 19.48!) but my trip computer showed 22.8. It generally is 3-4 mpg off in city driving. Maybe idling so much throws it off.
Traffic lights blow goats here. Cross street traffic lights change for no reason, 10 PM at night and the lights still operate on a morning rush hour cycle. I swear, traffic engineers are the stupidist people on the planet. Just kills my gas mileage and my average speed this last fill-up was 32 mph...and about 20% of my driving was on the freeway and the rest on streets with speed limits of 35 mph or higher. I've been averaging around 19.5 mpg since I got my car in mostly city driving...in fact, this last tank was 19.5 on the dot (okay, 19.48!) but my trip computer showed 22.8. It generally is 3-4 mpg off in city driving. Maybe idling so much throws it off.
#13
so you got a 03 max to save gas mileage compared to a 01? hmmm 3.0 to 3.5. check your numbers again buddy.
#14
spacers almost complete...
#16
Are you driving far enough for the car to fully warm up? How bad is the traffic where you live? Spend a lot of time idling at lights?
Traffic lights blow goats here. Cross street traffic lights change for no reason, 10 PM at night and the lights still operate on a morning rush hour cycle. I swear, traffic engineers are the stupidist people on the planet. Just kills my gas mileage and my average speed this last fill-up was 32 mph...and about 20% of my driving was on the freeway and the rest on streets with speed limits of 35 mph or higher. I've been averaging around 19.5 mpg since I got my car in mostly city driving...in fact, this last tank was 19.5 on the dot (okay, 19.48!) but my trip computer showed 22.8. It generally is 3-4 mpg off in city driving. Maybe idling so much throws it off.
Traffic lights blow goats here. Cross street traffic lights change for no reason, 10 PM at night and the lights still operate on a morning rush hour cycle. I swear, traffic engineers are the stupidist people on the planet. Just kills my gas mileage and my average speed this last fill-up was 32 mph...and about 20% of my driving was on the freeway and the rest on streets with speed limits of 35 mph or higher. I've been averaging around 19.5 mpg since I got my car in mostly city driving...in fact, this last tank was 19.5 on the dot (okay, 19.48!) but my trip computer showed 22.8. It generally is 3-4 mpg off in city driving. Maybe idling so much throws it off.
#17
or a freakin bicycle.. but i was expecting an improvement.. not for my gas spending to completely disappear
i thought there was something wrong with my car since i countinuously got 15-16 mpg no matter how slow i drove or what kind of roads i drove on.. plus manuals are better on gas than autos
i thought there was something wrong with my car since i countinuously got 15-16 mpg no matter how slow i drove or what kind of roads i drove on.. plus manuals are better on gas than autos
#19
On the display right now, it says 18.5 mpg... however, as I said before, I calculated it to be just over 15 when I filled up tonight. Why the huge discrepancy between those numbers? Am I calculating it wrong? My process: I reset my trip odometer everytime after I fill up. Then then next time I fill up, I take the number of miles I've driven, and divide it by the number of gallons it took to fill up the tank (Tonight I drove 204 miles and it took about 13.4 gallons to fill up). That's the right process to calculate it right? Why is my calculation so vastly different than the display on the car?
And although you shouldn't expect 30 mpg, the 15 mpg's that you are getting does seem low. With only 49K on the car your spark plugs should be fine but there could be another problem. I'm getting about 20 mpg's on my 2002 auto in the winter.
#22
I stopped caring about my Gas Mileage a long time ago..
Once I put the 6th gen tranny in my car, I knew I would lose my miles...
but... I will say I am a spirited driver, I shift between 3,500 RPM and 4,500 RPM as a daily... I get about 20 MPG (Display)... though my best was highway with my old trans, i got 36 MPG (Display)
Once I put the 6th gen tranny in my car, I knew I would lose my miles...
but... I will say I am a spirited driver, I shift between 3,500 RPM and 4,500 RPM as a daily... I get about 20 MPG (Display)... though my best was highway with my old trans, i got 36 MPG (Display)
#23
When I was a first-time shifter, I never got mileage as bad as yours, I was getting about 20-21. Just by learning better shifting habbits and becoming more experienced I now get 22-24 (city). So time will help a bit.
#25
My Calculation.
The week after I brought my car home, my display was around 23-24. Now it's at 32.
But by calculation I'm generally around 23 for city. It waivers depending on how spirited or nonspirited I'm feeling during the tank.
The week after I brought my car home, my display was around 23-24. Now it's at 32.
But by calculation I'm generally around 23 for city. It waivers depending on how spirited or nonspirited I'm feeling during the tank.
#27
Since we're on the topic of gas mileage:
Would higher elevations lower or increase gas mileage?
I would think it would matter and should be considered when talking about MPG.
Please correct if I'm wrong.
Would higher elevations lower or increase gas mileage?
I would think it would matter and should be considered when talking about MPG.
Please correct if I'm wrong.
#28
One thing I was wondering about is, if with the factory tune, our cars run rich, would adjusting the AFR with a SAFC2 help raise the gas mileage? I'm sure my car runs rich because every time I start it in the garage, it fumes it up bigtime. I drive 50city/50highway miles and I get right around 20-22 mpg.
#29
Altitude doesn't affect my mileage. AFC doesn't show any noticeable improvement since part throttle AFR is not and should not be altered. Never believe the trip computer, this has been established long ago. If you want to save MPG's, make sure the car is running tip top, get lightweight wheels, a different FD/6th gear and change your driving habits..
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#31
I get anywhere from 22 to 26 mpg, depending on driving conditions. And, yes, the car's computer is consistantly 4 mpg higher than the actual figure. Mid-teens is horrible.
#32
Similar issue here Bought a 2003 Maxima SE Auto with 48,000 miles on in a couple months ago in good condition from a reputable dealership. The dealership some basic maintenance on it before selling the car to us including an oil change, and engine air filter, and alignment.
Now after driving the car for a few months we've noticed some pretty poor gas mileage ratings. From the last two fill ups we're avg between 12-14 mpg! (calculated from the amount of miles driven from the trip computer vs the actual gallons used to fill up the tank) This is well below the Maxima's revised lower city rating of 17 mpg. I really don't have any explanation as to why it's so low and I'm concerned there might be something wrong with the engine. Although there isn't any obvious signs as to what might be causing this mileage drop.
I will note that:
- Our mileage has been almost all city driving vs hwy (90% city, 10% hwy)
- Have always used premium grade branded gas during fill ups
- Tire pressure was checked, no check engine lights or anything obvious is wrong with the car,
- Engine and transmission running smooth, no rough idle
- Outside temps have been in 40-50's outside when driving, but nothing super cold temps
- Car has been driving lightly, I don't floor it or drive aggressively.
- The carputer says that we're averaging 17.3 mpg which is way off from what our actual mileage has been
It's really interesting how varied people's mileage ratings are here and why ours is just plain lousy
Now after driving the car for a few months we've noticed some pretty poor gas mileage ratings. From the last two fill ups we're avg between 12-14 mpg! (calculated from the amount of miles driven from the trip computer vs the actual gallons used to fill up the tank) This is well below the Maxima's revised lower city rating of 17 mpg. I really don't have any explanation as to why it's so low and I'm concerned there might be something wrong with the engine. Although there isn't any obvious signs as to what might be causing this mileage drop.
I will note that:
- Our mileage has been almost all city driving vs hwy (90% city, 10% hwy)
- Have always used premium grade branded gas during fill ups
- Tire pressure was checked, no check engine lights or anything obvious is wrong with the car,
- Engine and transmission running smooth, no rough idle
- Outside temps have been in 40-50's outside when driving, but nothing super cold temps
- Car has been driving lightly, I don't floor it or drive aggressively.
- The carputer says that we're averaging 17.3 mpg which is way off from what our actual mileage has been
It's really interesting how varied people's mileage ratings are here and why ours is just plain lousy
#33
i did! i tried it last night for the first time and it worked nice.. i skip from 1st to 3rd, and 3rd to 6th.. i make sure to keep my rpms low to use as little gas as possible.. but i can't resist a 4-5k shift every now and then but that's not that often though.. i'm testing this tank of gas to see what my mileage is like using mostly low rpm shifts... and if it's STILL bad, i'm gonna switch gas stations.. because i should not be getting 15mpg... i heard certain stations can do weird stuff with their gas to throw off gas mileage.. and that actually would explain why my mpg has gone down over the 3-4 times i've filled up ever since i got the car.. hmm....
Last edited by wyche89; 01-02-2008 at 05:40 PM.
#35
Similar issue here Bought a 2003 Maxima SE Auto with 48,000 miles on in a couple months ago in good condition from a reputable dealership. The dealership some basic maintenance on it before selling the car to us including an oil change, and engine air filter, and alignment.
Now after driving the car for a few months we've noticed some pretty poor gas mileage ratings. From the last two fill ups we're avg between 12-14 mpg! (calculated from the amount of miles driven from the trip computer vs the actual gallons used to fill up the tank) This is well below the Maxima's revised lower city rating of 17 mpg. I really don't have any explanation as to why it's so low and I'm concerned there might be something wrong with the engine. Although there isn't any obvious signs as to what might be causing this mileage drop.
I will note that:
- Our mileage has been almost all city driving vs hwy (90% city, 10% hwy)
- Have always used premium grade branded gas during fill ups
- Tire pressure was checked, no check engine lights or anything obvious is wrong with the car,
- Engine and transmission running smooth, no rough idle
- Outside temps have been in 40-50's outside when driving, but nothing super cold temps
- Car has been driving lightly, I don't floor it or drive aggressively.
- The carputer says that we're averaging 17.3 mpg which is way off from what our actual mileage has been
It's really interesting how varied people's mileage ratings are here and why ours is just plain lousy
Now after driving the car for a few months we've noticed some pretty poor gas mileage ratings. From the last two fill ups we're avg between 12-14 mpg! (calculated from the amount of miles driven from the trip computer vs the actual gallons used to fill up the tank) This is well below the Maxima's revised lower city rating of 17 mpg. I really don't have any explanation as to why it's so low and I'm concerned there might be something wrong with the engine. Although there isn't any obvious signs as to what might be causing this mileage drop.
I will note that:
- Our mileage has been almost all city driving vs hwy (90% city, 10% hwy)
- Have always used premium grade branded gas during fill ups
- Tire pressure was checked, no check engine lights or anything obvious is wrong with the car,
- Engine and transmission running smooth, no rough idle
- Outside temps have been in 40-50's outside when driving, but nothing super cold temps
- Car has been driving lightly, I don't floor it or drive aggressively.
- The carputer says that we're averaging 17.3 mpg which is way off from what our actual mileage has been
It's really interesting how varied people's mileage ratings are here and why ours is just plain lousy
even with that much city driving it should be nowhere NEAR 12mpg.. V8s dont even get mileage like that.. try switching gas stations.. thats what im gonna do.. maybe it'll make a difference
#38
SIKE!! just joking.. dont flame me.. lol.. of course i use 93
Last edited by wyche89; 01-02-2008 at 05:49 PM.
#39
I'm wondering if I took it into an auto shop if they could even determine what the issue might be