Question about gas mileage! help Please
03-31-2014, 06:58 AM
#1
Junior Member
Thread Starter
Join Date: Mar 2014
Location: Camden,NJ
Posts: 85
Question about gas mileage! help Please
i have a question about gas mileage. when i fill up my tank with 93 octane, the computer reads i should have 398 miles to empty, driving efficiently i only get 230 miles per tank. i put 14 gallons in fuel. give or take a little off or more depending when i fill up. and usually about the same miles per tank.
i just got oil changed, plugs,pcv valve, rotate and balance. also i feel a very very slight misfire at idle.
i just got oil changed, plugs,pcv valve, rotate and balance. also i feel a very very slight misfire at idle.
03-31-2014, 11:36 AM
#7
A misfire will certainly affect fuel economy. There are MANY other factors as well....
It's been winter and if you've let the car warm up (which you should) then that will significantly affect fuel.
As mentioned, lots of city/ stop and go driving will consume more fuel. Even if conservative. Auto tranny can get worse fuel because of this. If a auto tranny is slipping, it can definately show.
Other maintenance issues as well - low tire pressure, seized brake caliper, or the known ebrake cable seizing issue, etc etc.
So, what to do? Ensure all maintenance is addressed. That includes inspecting brakes and making sure none are dragging. You can look at rotors for discoloration or even feel the center of the wheel with the back of your hand - if one wheel feels hotter than the other (left compare to right) then that wheel may be dragging. Don't compare front to rear as it should be expected fronts will be hotter.
If at a long red light, put the car in neutral or park (consumes less fuel). Eliminate any unnecessary weight if you have any. Carrying a toolbox, heavy sub/amp system, etc will pull fuel economy down the tubes.
Most important!! DO NOT measure fuel economy using the on board estimate system. Our tanks hold 18 gallons. If you fill 14 gallons- good - shouldn't run till dry. But, the ONLY way to get an accurate measurement of use is to divide the actual miles driven (means resetting trip each fill up) and dividing those miles by the number of gallons filled. That will give you your miles per gallon.
I get roughly 21mpg during winter. I get 23 in summer. Close to 25mpg on road trips. Consistent driving habits.
I'm sure there's more, but hopefully that's a start.
It's been winter and if you've let the car warm up (which you should) then that will significantly affect fuel.
As mentioned, lots of city/ stop and go driving will consume more fuel. Even if conservative. Auto tranny can get worse fuel because of this. If a auto tranny is slipping, it can definately show.
Other maintenance issues as well - low tire pressure, seized brake caliper, or the known ebrake cable seizing issue, etc etc.
So, what to do? Ensure all maintenance is addressed. That includes inspecting brakes and making sure none are dragging. You can look at rotors for discoloration or even feel the center of the wheel with the back of your hand - if one wheel feels hotter than the other (left compare to right) then that wheel may be dragging. Don't compare front to rear as it should be expected fronts will be hotter.
If at a long red light, put the car in neutral or park (consumes less fuel). Eliminate any unnecessary weight if you have any. Carrying a toolbox, heavy sub/amp system, etc will pull fuel economy down the tubes.
Most important!! DO NOT measure fuel economy using the on board estimate system. Our tanks hold 18 gallons. If you fill 14 gallons- good - shouldn't run till dry. But, the ONLY way to get an accurate measurement of use is to divide the actual miles driven (means resetting trip each fill up) and dividing those miles by the number of gallons filled. That will give you your miles per gallon.
I get roughly 21mpg during winter. I get 23 in summer. Close to 25mpg on road trips. Consistent driving habits.
I'm sure there's more, but hopefully that's a start.
03-31-2014, 11:46 AM
#8
Junior Member
Thread Starter
Join Date: Mar 2014
Location: Camden,NJ
Posts: 85
yes i do about 50/50 city/hwy, and my vehicle is a 6 speed. im wondering will a failing coil not throw a check engine light on, and will it just show a slight misfire? im thinking that might be the problem, because i already changed plugs, oil, pcv, tire rot and bal, belts. also my vehicle did not come with an air scoop(inlet) i just purchased one from another member. just wondering will this cause the problem.
03-31-2014, 01:53 PM
#12
Junior Member
Thread Starter
Join Date: Mar 2014
Location: Camden,NJ
Posts: 85
04-01-2014, 11:44 AM
#13
P0300 is multiple cylinders mis-firing. This means 2 or more cylinders. The little explosions may be the engine backfiring from too much unburned fuel in the catalytic converter.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
04-01-2014, 11:51 AM
#14
Junior Member
Thread Starter
Join Date: Mar 2014
Location: Camden,NJ
Posts: 85
P0300 is multiple cylinders mis-firing. This means 2 or more cylinders. The little explosions may be the engine backfiring from too much unburned fuel in the catalytic converter.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
bump
Last edited by NmexMAX; 04-02-2014 at 03:37 PM.
04-02-2014, 03:34 PM
#15
P0300 is multiple cylinders mis-firing. This means 2 or more cylinders. The little explosions may be the engine backfiring from too much unburned fuel in the catalytic converter.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
Unfortunately P0300 doesn't tell you which cylinders. Most of the time this is caused by the ignition coils failing, but not always.
A misfire will certainly affect fuel economy. There are MANY other factors as well....
It's been winter and if you've let the car warm up (which you should) then that will significantly affect fuel.
As mentioned, lots of city/ stop and go driving will consume more fuel. Even if conservative. Auto tranny can get worse fuel because of this. If a auto tranny is slipping, it can definately show.
Other maintenance issues as well - low tire pressure, seized brake caliper, or the known ebrake cable seizing issue, etc etc.
So, what to do? Ensure all maintenance is addressed. That includes inspecting brakes and making sure none are dragging. You can look at rotors for discoloration or even feel the center of the wheel with the back of your hand - if one wheel feels hotter than the other (left compare to right) then that wheel may be dragging. Don't compare front to rear as it should be expected fronts will be hotter.
If at a long red light, put the car in neutral or park (consumes less fuel). Eliminate any unnecessary weight if you have any. Carrying a toolbox, heavy sub/amp system, etc will pull fuel economy down the tubes.
Most important!! DO NOT measure fuel economy using the on board estimate system. Our tanks hold 18 gallons. If you fill 14 gallons- good - shouldn't run till dry. But, the ONLY way to get an accurate measurement of use is to divide the actual miles driven (means resetting trip each fill up) and dividing those miles by the number of gallons filled. That will give you your miles per gallon.
I get roughly 21mpg during winter. I get 23 in summer. Close to 25mpg on road trips. Consistent driving habits.
I'm sure there's more, but hopefully that's a start.
It's been winter and if you've let the car warm up (which you should) then that will significantly affect fuel.
As mentioned, lots of city/ stop and go driving will consume more fuel. Even if conservative. Auto tranny can get worse fuel because of this. If a auto tranny is slipping, it can definately show.
Other maintenance issues as well - low tire pressure, seized brake caliper, or the known ebrake cable seizing issue, etc etc.
So, what to do? Ensure all maintenance is addressed. That includes inspecting brakes and making sure none are dragging. You can look at rotors for discoloration or even feel the center of the wheel with the back of your hand - if one wheel feels hotter than the other (left compare to right) then that wheel may be dragging. Don't compare front to rear as it should be expected fronts will be hotter.
If at a long red light, put the car in neutral or park (consumes less fuel). Eliminate any unnecessary weight if you have any. Carrying a toolbox, heavy sub/amp system, etc will pull fuel economy down the tubes.
Most important!! DO NOT measure fuel economy using the on board estimate system. Our tanks hold 18 gallons. If you fill 14 gallons- good - shouldn't run till dry. But, the ONLY way to get an accurate measurement of use is to divide the actual miles driven (means resetting trip each fill up) and dividing those miles by the number of gallons filled. That will give you your miles per gallon.
I get roughly 21mpg during winter. I get 23 in summer. Close to 25mpg on road trips. Consistent driving habits.
I'm sure there's more, but hopefully that's a start.
I'll leave this here too:
Originally Posted by TunerMax3000
The PROPER way to calculate MPG is:
1. Fill tank completely
2. Reset odo
3. Drive as far as you feel like, doesn't matter much
4. Re-fill your tank completely
5. Record miles driven between #2 and #4
6. Record Gallons you put in tank at #4
7. Divide Mile reading you got at #5 by Gallon reading you got at #6
EXAMPLE:
1. Fill tank completely done
2. Reset odo 0 miles
3. Drive as far as you feel like, doesn't matter much 200 miles
4. Re-fill your tank completely done
5. Record miles driven between #2 and #4 200 miles
6. Record Gallons you put in tank at #4 8 Gallons
7. Divide Mile reading you got at #5 by Gallon reading you got at #6 200 Miles / 8 Gallons = 25 MPG
1. Fill tank completely
2. Reset odo
3. Drive as far as you feel like, doesn't matter much
4. Re-fill your tank completely
5. Record miles driven between #2 and #4
6. Record Gallons you put in tank at #4
7. Divide Mile reading you got at #5 by Gallon reading you got at #6
EXAMPLE:
1. Fill tank completely done
2. Reset odo 0 miles
3. Drive as far as you feel like, doesn't matter much 200 miles
4. Re-fill your tank completely done
5. Record miles driven between #2 and #4 200 miles
6. Record Gallons you put in tank at #4 8 Gallons
7. Divide Mile reading you got at #5 by Gallon reading you got at #6 200 Miles / 8 Gallons = 25 MPG
Last edited by NmexMAX; 04-02-2014 at 03:40 PM.
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