Horrible Gas Mileage
#46
12-01-2009, 09:19 AM
That's what did it, the stop and go. All cars are the most efficient when running at constant, low RPM at constant throttle. Any sort of acceleration/deceleration kills them on the highway.
For instance, on long trips, if I'm careful to drive at a constant speed or if I use the cruise control, I average almost 30 mpg, usually in the 29 mpg range (I'm ****, I keep track of mileage on a spreadsheet
). If I drive on the highway with a little more gusto, I get just over 20. It's all about how you drive. The best I was ever able to squeeze out of the car was about 32 mpg driving ~50 mph on long, straight country roads.
For instance, on long trips, if I'm careful to drive at a constant speed or if I use the cruise control, I average almost 30 mpg, usually in the 29 mpg range (I'm ****, I keep track of mileage on a spreadsheet
). If I drive on the highway with a little more gusto, I get just over 20. It's all about how you drive. The best I was ever able to squeeze out of the car was about 32 mpg driving ~50 mph on long, straight country roads.
#47
12-11-2009, 05:23 PM
Hi guys, I'm new to this forum and a first time G35 owner. I bought my 2004 G35 coupe about 6 weeks ago. to begin with i knew it wasn't a very fuel efficient vehicle but the gas mileage im getting is ridiculous. i do mostly city driving and i knew i probably wasn't going to get the 19mpg it says but im only getting 11.5-12 mpg on this car. i get only about 200 miles a tank. Service engine light isnt on. had the spark plugs replaced with new titanium tipped spark plugs, replaced the air filter, and i put premium Chevron gasoline. any recommendations you guys may have would be greatly appreciated. Engine Oil has been changed recently(when i bought it) and on a side note i drive it lightly, not lead footed at all. thanks in advance
#48
12-11-2009, 06:38 PM
check your PCV valve. Use some fuel treatment. I use Lucal Oil injector cleaner typically. I also have BG fuel treatment. I use it every 10K miles or so.
Consider changing spark plugs if you haven't yet. check the O2 sensor readings and A/F ratios if possible.
I have a 5AT and I average 20-21 MPG around town, and 25-29 MPG on the HWY.
With winter gas, I average about 19 MPG but that includes much longer warm up times and much less driving. I still get around 26 MPG when all HWY miles.
I have over 150K miles on my car now too.
Consider changing spark plugs if you haven't yet. check the O2 sensor readings and A/F ratios if possible.
I have a 5AT and I average 20-21 MPG around town, and 25-29 MPG on the HWY.
With winter gas, I average about 19 MPG but that includes much longer warm up times and much less driving. I still get around 26 MPG when all HWY miles.
I have over 150K miles on my car now too.
#49
12-11-2009, 08:44 PM
check your PCV valve. Use some fuel treatment. I use Lucal Oil injector cleaner typically. I also have BG fuel treatment. I use it every 10K miles or so.
Consider changing spark plugs if you haven't yet. check the O2 sensor readings and A/F ratios if possible.
I have a 5AT and I average 20-21 MPG around town, and 25-29 MPG on the HWY.
With winter gas, I average about 19 MPG but that includes much longer warm up times and much less driving. I still get around 26 MPG when all HWY miles.
I have over 150K miles on my car now too.
Consider changing spark plugs if you haven't yet. check the O2 sensor readings and A/F ratios if possible.
I have a 5AT and I average 20-21 MPG around town, and 25-29 MPG on the HWY.
With winter gas, I average about 19 MPG but that includes much longer warm up times and much less driving. I still get around 26 MPG when all HWY miles.
I have over 150K miles on my car now too.
Wow i wish i got 20 MPG! =p i love the car but sometimes i dont even feel like driving it knowing that no matter how careful i drive that needle is going down quick =/ i did change the spark plugs(platinum) and i tried a fuel treatment...changed the air filter as well...what year is yours? what are A/F ratios? can the O2 sensor be bad even if the check engine light isnt on? thx for the reply! if the gas mileage was what it says it should be this car would be perfect. mine has 70k miles and everything else is flawless
#51
12-11-2009, 11:05 PM
The cars getting the worst mileage probably need tune-ups but with cold temps two things are working against good mileage, cold wet air requires more fuel to maintain the a/f ratios, your car will make more power but if you press the throttle like usual you'll be using more fuel, second, in cold weather it takes longer for the engine to reach temp, until it does it runs on the start-up map which is very rich, like running with the choke on back in the carb days. Throw in the extra ethanol and expect 10%-15% less mileage.
#52
12-11-2009, 11:19 PM
#53
12-12-2009, 01:20 AM
#54
12-19-2009, 04:12 PM
Went to a mechanic who has a computer that checks everything(not the simple code detectors). O2 sensors are working just fine and pcv valve is not a problem. the computer checked a bunch of other things and nothing was detected. said everything looked perfect and that it's something the computer doesnt detect. im now at my wits end. idk what to do with this car. he recommended to wait for the service engine light to hopefully turn on again and he'll recheck it. also mentioned doing a fuel injection cleaning. <sigh> =/
#55
12-19-2009, 05:13 PM
Driving style plays a huge role. I notice that when i try, i can get around 21 MPG ave city/highway if i actually drive the car easy and don't get hard on the throttle from a stop.
But if i drive just a little spirited it drops to maybe 15-17MPG in the city.
Oh the highway, once i get up to speed and reset the mileage indicator in my NAV, i can get like 25-26MPG while cruising. I once drove 3 hours continuous averaging around 25MPG, but noticed if i were to give it some gas to pass cars it would drop like a rock.
I just think driver's style plays a huge role in the fuel economy. Maybe some of the guys with poor economy is just due to how they drive vs an actual mechanical condition. I've found that i get the same poor fuel economy if i'm not alert. Amazingly i seem to be able to get better fuel economy when my low fuel light comes on vs when my tank is full just because i;m trying to stretch my "25 miles to empty" an additional 15 miles to the next gas station. When my tank is full, i just gun the throttle
But if i drive just a little spirited it drops to maybe 15-17MPG in the city.
Oh the highway, once i get up to speed and reset the mileage indicator in my NAV, i can get like 25-26MPG while cruising. I once drove 3 hours continuous averaging around 25MPG, but noticed if i were to give it some gas to pass cars it would drop like a rock.
I just think driver's style plays a huge role in the fuel economy. Maybe some of the guys with poor economy is just due to how they drive vs an actual mechanical condition. I've found that i get the same poor fuel economy if i'm not alert. Amazingly i seem to be able to get better fuel economy when my low fuel light comes on vs when my tank is full just because i;m trying to stretch my "25 miles to empty" an additional 15 miles to the next gas station. When my tank is full, i just gun the throttle
#58
01-02-2010, 03:27 PM
#59
01-02-2010, 04:10 PM
My navi says 16.4 now with stop and go highway traffic, I do punch it from time to time. Suck for me cause my maxima would get 330miles to a tank driving the same way
2005, auto, 52k miles, new plugs, recent oil change, z-tube, test pipes, intake spacer, up-rev reflash tuned for 12.8-13.0 a/f
2005, auto, 52k miles, new plugs, recent oil change, z-tube, test pipes, intake spacer, up-rev reflash tuned for 12.8-13.0 a/f