15~16 miles/gal.(premium)
12-13-2007, 10:22 PM
#1
15~16 miles/gal.(premium)
Hi.
I don't have any CEL and all of the O2 sensors and knock sensor were replaced 3 month ago. After all the sensors replaced, it made 20~21 miles/per for about 1 month. But now the gas mileage is 15~16 mile/gal. The car, which is 96' 132k on it, is always feeded on Shell premium only. What could be wrong with the horrible gas mileage?
O2 sensors?
Knock sensor?
Any other problem?
What can I do?
Thanks.
I don't have any CEL and all of the O2 sensors and knock sensor were replaced 3 month ago. After all the sensors replaced, it made 20~21 miles/per for about 1 month. But now the gas mileage is 15~16 mile/gal. The car, which is 96' 132k on it, is always feeded on Shell premium only. What could be wrong with the horrible gas mileage?
O2 sensors?
Knock sensor?
Any other problem?
What can I do?
Thanks.
12-13-2007, 10:32 PM
#2
yah my car gets around the same gas mileage. On average how many miles per tank? I can never break 300. Also i mainly drive to and from school which isnt alot of highway and alot of stop and go. So driving conditions can affect gas mileage too.
12-13-2007, 10:38 PM
#3
I used to get 300 to the tank also, but now i get around 430 to the tank using premium and driving it hard. I do mostly highway miles so i get around 28 mpg, but in city i get around 21mpg. Try using some Lucas Fuel Injector Cleaner, it works wonders 
. You can also clean out your TB, it will make the throttle response much better and smoother.
. You can also clean out your TB, it will make the throttle response much better and smoother.
12-13-2007, 10:46 PM
#4
Ha! I should be so lucky. I can't break 230 on a tank, v-power shell. Or any 89 or 93 octane gas. My car is still being worked on .... new iridium spark plugs, clean idle speed control valve and throttlebody, new fuel filter, new goodyear eagle f1 all seasons for the front, rear motor mount, new oem lower radiator support, and new undershields.
Once I get the car back from the shop, we will see how much I get per tank. My mechanic said that mileage goes down with the winter blended gas as well, I wonder how true that is.
Once I get the car back from the shop, we will see how much I get per tank. My mechanic said that mileage goes down with the winter blended gas as well, I wonder how true that is.
12-13-2007, 10:57 PM
#5
Wow. It sounds like you guys/gals are mostly up on maintenance.. that kind of mileage seems quite low. Granted I don't drive overly hard and most my driving is mixed city/hwy but most people in your situation get AT LEAST 18mpg. Something must be wrong imo. Have you checked for gas/air leaks? The reason I mention that is last winter I added a fstb to my car but it was designed for 3rd gens and actually broke a small hose, dropping my gas mileage a good 2-3mpgs.
12-13-2007, 11:11 PM
#6
What does that mean?
Join Date: Apr 2007
Location: Calgary, AB
Posts: 393
Yeah that's pretty ridiculous, the past two tanks I've gotten about 350 miles per tank, and that's with a o2 sensor code, knock sensor code, 2 heavy tool boxes in the trunk, and it turns out my rear tires were underinflated at only 20 psi. All city driving, although almost always in the evenings when traffic is light... any chance brakes are dragging slightly? done a compression test lately?
12-14-2007, 12:36 AM
#7
Supporting Maxima.org Member
iTrader: (29)
Join Date: Oct 2005
Location: Middleboro/Carver, Ma
Posts: 4,572
Let's start by checking 4 things:
Check all fluid levels & conditions
Scan for ghost codes
Jack up each wheel and make sure they spin freely.
Check long-term fuel trims for B1 & B2 (obdII scanner required)
Check all fluid levels & conditions
Scan for ghost codes
Jack up each wheel and make sure they spin freely.
Check long-term fuel trims for B1 & B2 (obdII scanner required)
12-14-2007, 03:34 AM
#9
wow, 40 psi is really high unless you have bigger tires than stock, i have nitogen and stock tire size and its 33 psi. and the guy that said hes getting 430 miles per tank is foc, unless hes drivin like the exact speed limit all the time. 300 to 350 miles per tank is normal for our cars, fluids in my car are all fresh and topped off and i never get any better than that. thats a 4th gen for ya.
Last edited by max ride 41; 12-14-2007 at 03:36 AM.
12-14-2007, 03:35 AM
#10
I got 16.777 mpg last time I filled up (297mi/17.5gal) and it has been a constant decline since cold weather has started. I never got great gas mileage to begin with (always averaged about 18-19 city and 24-26 highway) but I think short 2 mile trips to school, warming up the car 5 mins early in the AM, and having some fun in the snow don't help my MPG very much.....
12-14-2007, 05:12 AM
#11
Hi.
I don't have any CEL and all of the O2 sensors and knock sensor were replaced 3 month ago. After all the sensors replaced, it made 20~21 miles/per for about 1 month. But now the gas mileage is 15~16 mile/gal. The car, which is 96' 132k on it, is always feeded on Shell premium only. What could be wrong with the horrible gas mileage?
O2 sensors?
Knock sensor?
Any other problem?
What can I do?
Thanks.
I don't have any CEL and all of the O2 sensors and knock sensor were replaced 3 month ago. After all the sensors replaced, it made 20~21 miles/per for about 1 month. But now the gas mileage is 15~16 mile/gal. The car, which is 96' 132k on it, is always feeded on Shell premium only. What could be wrong with the horrible gas mileage?
O2 sensors?
Knock sensor?
Any other problem?
What can I do?
Thanks.
i noticed you didnt have FUEL FILTER or AIR FILTER on your list. make sure to check/replace those. should cost no more than 20 dollars and an hour or two.
you should also be checking your intake for leaks/dirt in the IACV and TB.
im gettin 350+ driving hard - in a city environment (lights every mile)
i rarely use the highways. maintenance items ive done:
new KS
new platinum plugs
tire pressure is 31-33
new OEM air filter
only using 93
on checking for ghost codes (ks.....) and checking if wheels are spinning with minimal friction
12-14-2007, 09:02 AM
#15
Over the years here on the .org, I have noticed this when this style thread comes up. Other veterans here help me see if I am correct. I know this is how most other cars work, but usually an AUTOMATIC trans car with get ~ 10mpg less than a Standard shift. I noticed on this list of posters also. The people getting upper 20's not only drive freeway, but have a standard.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65 on standard 87 oct gas) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65 on standard 87 oct gas) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
Last edited by alcatranz518; 12-14-2007 at 09:27 AM.
12-14-2007, 09:20 AM
#16
AUTO gets 20-22 city and 24.5 with even 50% highway which is perfect (8 gallons x 21 mpg city = 168 and 8x28mpg highway = 224 total of 394 miles over 16 gallons =24.5mpg for full tank) never driven a full tank on highway. I also live in the regulated gas area of Wisconsin so if i used normal gas i would tack on 1~2 more mpg. In the winter it gets bad around here, i don't use overdrive to heat car faster and i hear there is a winter blend gas here. You should get 20 mpg city, other wise something needs to be replaced. Infiniti parts car i got, last owner reported 26 mpg with highway driving. Something you over looked, you put in the right time, in the right place she will put out!!!!!!!!!!!!!!
12-14-2007, 09:24 AM
#17
Over the years here on the .org, I have noticed this when this style thread comes up. Other veterans here help me see if I am correct. I know this is how most other cars work, but usually an AUTOMATIC trans car with get ~ 10mpg less than a Standard shift. I noticed on this list of posters also. The people getting upper 20's not only drive freeway, but have a standard.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
12-14-2007, 10:17 AM
#19
I agree with the person saying auto and 5 speed. My maintence is so-so I have a 5 speed 97 GXE with Sunoco 93 I get 430 miles per tank still with not lighting the yellow gas light. Yes I drive mostly Highway with no traffic proper shifting on the avg 3500 revs sometimes even 4000 but not going over 95 but a constant 75-85 so I did not know the automatics are so bad. I do have proper tire pressure, high speed balanced, and alignment. Michelin tires and the tight suspension has helped out alot on the braking so I feel I getting better mileage. The maxima is giving way better mileage in gas than other smaller engines because they can not handle the highway speeds.
12-14-2007, 03:41 PM
#22
What does that mean?
Join Date: Apr 2007
Location: Calgary, AB
Posts: 393
12-14-2007, 05:43 PM
#23
12-14-2007, 05:46 PM
#24
yea im lazy too
12-14-2007, 07:46 PM
#26
Over the years here on the .org, I have noticed this when this style thread comes up. Other veterans here help me see if I am correct. I know this is how most other cars work, but usually an AUTOMATIC trans car with get ~ 10mpg less than a Standard shift. I noticed on this list of posters also. The people getting upper 20's not only drive freeway, but have a standard.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65 on standard 87 oct gas) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
My Auto will not get over 22mpg on the highway, thats doing exactly 65 (cruise control) to Niagara falls and back (which is one full tank trip and only two stops including one to the rest stop). Just background, I have all new wheel bearings, knock/O2 sensors, etc., running premium all the time and not to mention a maintenance schedule that is religious (granted it has 180,000miles on it).
My Civic-the beater- is another good example. I get 38mpg (using cruise control also set at 65 on standard 87 oct gas) with it, but is a 5spd (and it has 200,000 miles on it HAHA - show me a Cavalier that can do that). The auto Civics only get around 28-30mpg highway. I drove it to Niagara Falls also which was a 3/4 tank trip.
FYI: Niagara Falls is exactly 414 miles round trip for me with NO stops unless I need a drink or go pp (lol).
My Point: The Autos avg ~18-22mpg, the Standards avg ~25-30 mpg. The 5/6 speeds can be better depending flywheel weight and shifting/ driving habits. Our Autos suck so bad b/c of gearing, but mainly the torque converter weight...so how much to do a swap? I think thats gonna be my next mod. I've contemplated doing before, the mpg is my selling point.
Well I think I'm gonna have to disagree with you there. I live in the Rochester, NY area and have a friend in Columbus. Granted I do have a 5spd. but my mileage when visiting her is roughly 27mpg to Columbus and 32mpg on the way back. As I'm sure you know the wind is pretty stiff on I-90 (I assume you travel that route) and is the reason mileage differs so much each way. I cruise at 74-76 all the time. I have to assume and would bet there's something wrong that's limiting your mileage. In mine and my father's exp (he's owned 2 max's) the manuals get a lil better mileage in city/mixed normal driving while at hwy the mileage is essentially the same.. that's in our family. I just can't believe your auto can't get over 22mpg and at 65mph, it just doesn't make sense. Maybe I'm wrong but that's my experience. Even if you have mods that slightly lower mpg it shouldn't make that much of a difference. I don't know, if you were driving 90 each way then it'd make more sense to me.
12-14-2007, 09:15 PM
#27
Thats what drove me to replace everything and clean as thoroughly as possible, replacing sensors bearings etc. I do not drive erratic, yet my max will NOT get better gas mileage than 22mpg. Unless maybe I did overlook something. Then as time progressed, I always would notice many other Auto owners saying theirs got roughly the same. Whereas most manual owners never seemed to claim under 25 and up to 30, if not more. I wasn't claiming it to be a huge finding, just something I'd noticed and pay'd attention to reading over the past 3 years. 
12-14-2007, 09:17 PM
#28
I don't get why people believe that just because you drive a stick you can't multitask. I can switch gears while talking on the phone and playing with my ipod. Once you get used to the feel of your cars shift points it becomes automatic for you, i don't even think while switching gears, i just do it because i can hear when its time by the engine and i know at what mph i should switch it at.
12-14-2007, 09:21 PM
#29
yeah, i never really pay attention when someone says they get bad mileage in city/mixed driving because there are so many factors going into it, but on the hwy with cruise on is where it seems way out of whack, unless people are driving up mountains 
Thats what drove me to replace everything and clean as thoroughly as possible, replacing sensors bearings etc. I do not drive erratic, yet my max will NOT get better gas mileage than 22mpg. Unless maybe I did overlook something. Then as time progressed, I always would notice many other Auto owners saying theirs got roughly the same. Whereas most manual owners never seemed to claim under 25 and up to 30, if not more. I wasn't claiming it to be a huge finding, just something I'd noticed and pay'd attention to reading over the past 3 years.
12-14-2007, 11:58 PM
#30
Mine is Auto tranny. The air filter, fuel filter, and spark plugs were replaced a month ago. And I don't have any CEL. When the O2 sensors and knock sensor were just replaced three month ago, the car made up to 330mile by 16 gal.(premium). By the way it was only 3 times happen. After the 3 times made the normal mileage, it get back to the 250 miles again so far. I don't know why??? It wasn't changed anything. The car is driving the same distance and time because I'm a full-time student. I just doubt the front two of O2 sensors are UNIVERSIAL so they could be something wrong even though they don't show the CEL to me.
Thanks.
Thanks.
12-15-2007, 06:35 AM
#31
Senior Member
Join Date: May 2004
Posts: 6,190
I consistently get over 500 miles to a tank on straight highway driving. I have exceeded 550 miles, about 3 or 4 times. The vehicle is a 5-speed.
Canadian gasoline is better than US gasoline.
Automatics are supposed to get slightly better fuel economy on the highway and slightly lower fuel economy in the city.
I over inflate my tires to about 36 front, 35 rear.
Tire pressure should be checked more frequently in colder weather as radial tires can lose about 2 pounds per month.
Canadian gasoline is better than US gasoline.
Automatics are supposed to get slightly better fuel economy on the highway and slightly lower fuel economy in the city.
I over inflate my tires to about 36 front, 35 rear.
Tire pressure should be checked more frequently in colder weather as radial tires can lose about 2 pounds per month.
12-15-2007, 01:59 PM
#32
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
Example, the BMW 3 series and yes, I own one.
Perhaps you should increase your crusing speed.
12-16-2007, 09:34 AM
#33
Car is garage kept over winter, so no drivy-drivy in cold weather/snow. I have no ghost codes, TB/mani cleaned every spring, all new calipers and wheel bearings, new knock sensor, new copper plugs every 30,000 miles, FF changed every 3500 miles, air filter cleaned at same. Premium gas always. Car runs/idles perfect except for mileage.
So what could it be? I ran out of options.
Last edited by alcatranz518; 12-16-2007 at 09:43 AM.
12-16-2007, 10:37 AM
#34
Senior Member
Join Date: May 2004
Posts: 6,190
I'm not sure what the problem is. What tire pressure do you use?
There is absolutely no need to replace the fuel filter every 3500 miles. I replace mine every 30k as called for.
Cleaning the throttle body and manifold every spring is more than a tad ****!
There is absolutely no need to replace the fuel filter every 3500 miles. I replace mine every 30k as called for.
Cleaning the throttle body and manifold every spring is more than a tad ****!
Haha, don't I wish...When I cruise at 80 (which is rarely) I can almost watch my gas gauge fall.
Car is garage kept over winter, so no drivy-drivy in cold weather/snow. I have no ghost codes, TB/mani cleaned every spring, all new calipers and wheel bearings, new knock sensor, new copper plugs every 30,000 miles, FF changed every 3500 miles, air filter cleaned at same. Premium gas always. Car runs/idles perfect except for mileage.
So what could it be? I ran out of options.
Car is garage kept over winter, so no drivy-drivy in cold weather/snow. I have no ghost codes, TB/mani cleaned every spring, all new calipers and wheel bearings, new knock sensor, new copper plugs every 30,000 miles, FF changed every 3500 miles, air filter cleaned at same. Premium gas always. Car runs/idles perfect except for mileage.
So what could it be? I ran out of options.
12-16-2007, 12:44 PM
#36
Yup thats what I was going to add to this. In most cases cars with manuals get better mpg than their automatic siblings do. I bought a 99 5sp that I gave to my brother (this was before I got my 98 auto) and when I went from driving my 98 to his 99 I noticed that the 99 had a significant difference in cruising RPMs at lets say in the 70-75mph range. The only way I get 400+ mpg in my 98 is when on a road trip. I once got about 530 miles when I was trailering a big rig who was cruising at about 85 for 3 hours.
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