Am driving 2004 MDX with 3.5liter engine capacity and recently i notice my fuel consumption has drop from 15 or 16 MPG on average to 8.1MPG, my daily driving to work is always against the traffic, no change in route and no matter how free the road is i don't get more than 12.1MPG now.

No check engine light or code display to indicate any fault and their is no pending code either.
I trend the Short and Long fuel trim to see if the vehicle is running lean or rich but values seems to be within acceptable range

STFT1 value: -1.6%, STFT2 Value: -0.8% to 1.6%.
LTFT1 Value: -3.1%, LTFT2 Value: -0.8%

AFR Value: 14.7:1, though this fluctuate between 14.5 to 14.8 but more steady at 14.7:1

17MPG is the expected value for city driving but i usually get 15MPG - 16MPG and this has drop to 8.1MPG, everything seems normal except for the MPG. below is the Oxygen sensor graph.

At this point we know your loss in MPG shouldn't be engine related maybe you should look at tires, bearings, breaks or your transmission is about to go bad.

icemann:
At this point we know your loss in MPG shouldn't be engine related maybe you should look at tires, bearings, breaks or your transmission is about to go bad.

Thanks, am yet to check the tire pressure but my dash board didn't indicate deflation in any on the wheels. the front brake pads are low actually but can't see any correlation with the issue. bearing, don't know about that, how do you check

domack99:


Thanks, am yet to check the tire pressure but my dash board didn't indicate deflation in any on the wheels. the front brake pads are low actually but can't see any correlation with the issue. bearing, don't know about that, how do you check

Are you trolling?
When i say brakes i mean check if the brakes are binding. And bearings are nosy when worn out.
How did you get your MPG? From the car display? Did you reset it?

icemann:


Are you trolling?
When i say brakes i mean check if the brakes are binding. And bearings are nosy when worn out.
How did you get your MPG? From the car display? Did you reset it?

Yes, the MPG is from the car trip computer. It reset on a daily basis, that's how i configured it, either reset daily, reset of refill or no reset at all, it gives the same value on the long run.

And no bearing sound as well.

first would like to add that most car computer generated mpg are not accurate.. the best way to calculate your mpg is to do so manually i.e reset your trip meter during fillup.. fill your tank, then drive.. when your guage is in half tank or u are about to do your next fill up note the amount of liters it takes to fill up (usually you have to convert the liters to gallons - lots of smart phone app can do that) then divide the amount of miles covered by your trip meter with the number of gallons it takes to fill the car. example

I reset my trip meter to 0 fill my tank and drove off..
in my next fill up.. (the fuel gauge is at the mid way point) I have covered 220 Miles.. and 23 liters was used to refill the tank 23 liters = 6.0759572 so to get my mpg i do 22/6.0759572 = 36.666666667.. so my mpg is approximately 37.

Please note that where you get your fuel is very important. due to the sharp practices of most of our filling stations, I have chosen to only get fuel from a particular filling station (from a particular tank) I was getting really bad mpg before releasing that I was inputting the wrong data thanks to gas stations sharp practices.

Also note that city driving differs.. being stuck in a driglock for hours should not be compared to general stop and drive traffic.. or general non traffic drive around town (which is still city driving)

Easy things I would advise your try out:

Clean your air filter, inspect your spark plugs and change if it doesn't look healthy (you would know), inspect the state of your gear oil.. also inspect your break calipers to see if it is bonding (one easy way to do this is to put the car on neutral (from a stationary position)on a slightly slipper ground and see if it moves.. you could have your mechanic inspect it too.

Also driving habits helps alot.. I was able to improve my mpg from 21 to 27 when I slowed down on the lead foot.. I generally resulted to cruising at around 75-80km/h even when am on the free way.. this allows me drive without applying breaking unnecessarily while resorting to smart switching of lanes.. yes this makes me drive like a grand mother, but also good for my pocket.. I am currently doing 512KM (318 miles) on a 55 liter capacity car and am at 3/4 of my tank all thanks to change in driving habit.

Thanks @bigrovar,

I changed the rear brake pad and also adjust the hand brakes not to long ago, i will say almost the same time i start noticing this issue, might be a mere coincident or a contributing factor. i will work on that.

The car trip computer has been given me a satisfactory value previously, i don't think is not accurate as you mentioned. will also do your own calculation as well an see what value i will be getting.

bigrovar:
first would like to add that most car computer generated mpg are not accurate.. the best way to calculate your mpg is to do so manually i.e reset your trip meter during fillup.. fill your tank, then drive.. when your guage is in half tank or u are about to do your next fill up note the amount of liters it takes to fill up (usually you have to convert the liters to gallons - lots of smart phone app can do that) then divide the amount of miles covered by your trip meter with the number of gallons it takes to fill the car. example

I reset my trip meter to 0 fill my tank and drove off..
in my next fill up.. (the fuel gauge is at the mid way point) I have covered 220 Miles.. and 23 liters was used to refill the tank 23 liters = 6.0759572 so to get my mpg i do 22/6.0759572 = 36.666666667.. so my mpg is approximately 37.

Please note that where you get your fuel is very important. due to the sharp practices of most of our filling stations, I have chosen to only get fuel from a particular filling station (from a particular tank) I was getting really bad mpg before releasing that I was inputting the wrong data thanks to gas stations sharp practices.

Also note that city driving differs.. being stuck in a driglock for hours should not be compared to general stop and drive traffic.. or general non traffic drive around town (which is still city driving)

Easy things I would advise your try out:

Clean your air filter, inspect your spark plugs and change if it doesn't look healthy (you would know), inspect the state of your gear oil.. also inspect your break calipers to see if it is bonding (one easy way to do this is to put the car on neutral (from a stationary position)on a slightly slipper ground and see if it moves.. you could have your mechanic inspect it too.

Also driving habits helps alot.. I was able to improve my mpg from 21 to 27 when I slowed down on the lead foot.. I generally resulted to cruising at around 75-80km/h even when am on the free way.. this allows me drive without applying breaking unnecessarily while resorting to smart switching of lanes.. yes this makes me drive like a grand mother, but also good for my pocket.. I am currently doing 512KM (318 miles) on a 55 liter capacity car and am at 3/4 of my tank all thanks to change in driving habit.

Pls wat kind of car do u drive and wat kind of engine is on it?

domack99:


Yes, the MPG is from the car trip computer. It reset on a daily basis, that's how i configured it, either reset daily, reset of refill or no reset at all, it gives the same value on the long run.

And no bearing sound as well.

What type and where did get that scanner?

icemann:


What type and where did get that scanner?

Seems you quote the wrong part, i use ELM327 with Torque Pro android app. The MPG is display on the trip computer, a display panel that comes with MDX.

domack99:


Seems you quote the wrong part, i use ELM327 with Torque Pro android app. The MPG is display on the trip computer, a display panel that comes with MDX.

You are not a learner. You probably know more about cars than i do.

hkwills:


Pls wat kind of car do u drive and wat kind of engine is on it?

Its a 2.3L Engine that came with the Mazda 3 SP23 (2006).. I should point out the above MPG was gotten doing mostly high way driving at grandma speed (75-85km/h) city driving will give me a considerably lesser mpg with about 23 or even 22

domack99:
Thanks @bigrovar,

I changed the rear brake pad and also adjust the hand brakes not to long ago, i will say almost the same time i start noticing this issue, might be a mere coincident or a contributing factor. i will work on that.

The car trip computer has been given me a satisfactory value previously, i don't think is not accurate as you mentioned. will also do your own calculation as well an see what value i will be getting.

Another thing which won't hurt is to clean your MAF.. a dirty MAF can result to excessive fuel consumption without triggering any code.. Please do not attempt to clean your MAF with Carburetor as this would damage the MAF instead get a dedicated MAF cleanning spray (CRC MAF CLEANER) unfortunately you can get one off the shelve here in Nigeria. The one I used for my car, I got it from a friend in abuja.. idaraa (or something like that met him on NL) you can also use Spirit.

Your readings seem normal, therefore the problem is either the quality of fuel or sticky brakes.

I would guess it's the fuel though

nissparts:
Your readings seem normal, therefore the problem is either the quality of fuel or sticky brakes.

I would guess it's the fuel though

Its definitely not the fuel, if it were the STFT value would be above 10%. That car is running fine the guy is just trolling he knows about cars.

bigrovar:


Its a 2.3L Engine that came with the Mazda 3 SP23 (2006).. I should point out the above MPG was gotten doing mostly high way driving at grandma speed (75-85km/h) city driving will give me a considerably lesser mpg with about 23 or even 22

Ok tanks
Mine is Honda accord 2002 model V6 engine
It doses from from full tank to half tank on 202miles .cos I do rest d millage d moment I fill up d tank. City driving precisely. It's d. Consumption fair enough for a V6?

icemann:


Its definitely not the fuel, if it were the STFT value would be above 10%. That car is running fine the guy is just trolling he knows about cars.

Please don't get me wrong, that's the situation am presently in now, its always much more easier to diagnose when the system throw a code.
At least i have idea on where to start looking based on the responses so far, will give feedback if there is any improvement

All ur parameters seem fine. I think it depends on ur average driving distance. I used to get mpg of 21 when my work place was far from my house. Now I get 8.5mpg. No CEL, no change in performance, not even in fuel consumption. Only difference is my workplace is now a stone throw from my house. If u commute very short distance, u will get dat. Once in a while when I hit highway, I get upto 29mpg

chukel:
All ur parameters seem fine. I think it depends on ur average driving distance. I used to get mpg of 21 when my work place was far from my house. Now I get 8.5mpg. No CEL, no change in performance, not even in fuel consumption. Only difference is my workplace is now a stone throw from my house. If u commute very short distance, u will get dat. Once in a while when I hit highway, I get upto 29mpg

Thanks, but the route remain the same, i will try and hit the high on Sunday when the road is free and see if there would be any improvement.

Is your rear brake disc or drum? If it is drum, I am afraid the mechanics may have adjusted it to be too tight and it is now binding. Lift your rear tyres without the handbrakes on and spin them. They should be able to spin freely without much effort. Also diesengage the transmission if ur ride is a rear wheel drive while performing this test. This will let you know if the mechanics did the ajdustments properly after changing ur pads. Mine was once set so tightly that it condemned my rear drums in one month not to mention the horrible gas mileage I got before I figured it out.

Hi guys, I drive a Nissan Xterra 2003 model.. given to me by a brother.. but have noticed the car is consuming h.ell amount of fuel. Most time spend 2000 to 2500 from Ojota to Magodo > Yaba then Back to Ojota.....

But my friend driving a Nissan pathfinder 1999 model do this same trip with 1500 fuel and still have some to Go church the next day (church distance like from Ojota to Oregun daystar church)

But my own car will already be Out of fuel...
I scanned with a small OBD device and it gave me this code.


"Fault log report generated by Torque for Android
=================================================

Vehicle VIN: Not present
Vehicle Manufacturer: Unknown
Vehicle Calibration ID: 1EK816

VX133S

Current Fault Log
------------------
P0505: Idle Control System
P0335: Crankshaft Position Sensor A Circuit
P0745: Pressure Control Solenoid "A"
P0455: Evaporative Emission Control System Leak Detected (gross leak)
P0037: HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
P0328: Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)

Pending Fault Log
------------------
P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)"




Please Help me oo.. Before the car finish my pocket..

domack99:
Am driving 2004 MDX with 3.5liter engine capacity and recently i notice my fuel consumption has drop from 15 or 16 MPG on average to 8.1MPG, my daily driving to work is always against the traffic, no change in route and no matter how free the road is i don't get more than 12.1MPG now.

No check engine light or code display to indicate any fault and their is no pending code either.
I trend the Short and Long fuel trim to see if the vehicle is running lean or rich but values seems to be within acceptable range

STFT1 value: -1.6%, STFT2 Value: -0.8% to 1.6%.
LTFT1 Value: -3.1%, LTFT2 Value: -0.8%

AFR Value: 14.7:1, though this fluctuate between 14.5 to 14.8 but more steady at 14.7:1

17MPG is the expected value for city driving but i usually get 15MPG - 16MPG and this has drop to 8.1MPG, everything seems normal except for the MPG. below is the Oxygen sensor graph.

Were you able to fix the fuel consumption