| Sudden Drop In Gas Mileage
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| mdxgray |
After approx. 70K miles on my '01 the mileage has dropped 2-3 mpg. I have checked on all driving conditions and the change is real. I contacted my dealer and he told me unless a warning light came on they could not determine what the problem was. Has anyone else had a similar occurance? Unitil this happened I have been very pleased with my mileage. I have tried all grades of fuel and haven't been able to tell any difference but I have stuck with the middle grad all along.
Thanks
mdxgray |
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| EXCALIBUR |
mdxgray,
Q: Have you checked to make sure that you have a clean air filter?:confused: |
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| G. COLTON |
More information is needed.
Was the drop sudden or was it gradual? What were the mpgs before and after?
Are you basing your statement on the trip computer or actural calculation of miles driven and gallons used. If based on calculations how many miles/gallons were used to make the calculation.
KDoes there seem to be a difference between open road and city driving?
G |
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| mdxgray |
| Drop in mileage was sudden. Never trust trip computer, all averages based on actual miles and gallons to fill up. All types of driving effected. Have put over 4K miles on since it dropped and it is without a doubt lower than before. Before the drop I was getting an average of 19.5 in mixed driving with over 21 mpg on Interstate at 75mph. Now I am on getting at best 19-19.5 mpg. on interstate. Have not checked the air filter as it is not easy to get out but the dealer has done all of the services on time and I am assuming they changed it as needed. |
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| ScoobyT |
| Did u switch to a different gas, octane, brand? |
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| Gregc |
The mileage suddenly dropped on my 01, then followed by hard starting and the check Engine light. If you have a OBDII scan tool take a look at your long term Fuel trim. The issue may be your EGR valve is going bad. To correct for this the computer adjusts the amount of fuel injected in the engine. It could also be a bad O2 sensor, you realy need someone to look at how the fuel injection system is functioning. The EGR is a common replacement part and runs around $95 and 2 bolts and 10 minutes to replace.
Greg |
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| nwaring |
Nothing scientific but we noticed and discussed several times over the winter that the gas mileage on our 01 just wasn’t what it used to be. About a month ago we got the VTM-4 and check engine light combo, which normally is the EGR. I ordered one from Tim, installed it. On our very next 200 mile or so trip it appeared the mileage was back to our normal.
Good luck
Niles |
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| mdxgray |
| This week I took it in for the 75,000 mile checkup and asked them to check the engine, etc out for the drop in mileage. They said everything looked good and they could not find the problem. Can the EGR or the O2 sensors go bad and the dealer not be able to detect it? |
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| Gregc |
Yes the EGR valve can definitly go bad with no errors being logged by the ECM. The way the ECM determines if the EGR is working properly is by the signals the EGR valve sends back when EGR lift is called for. If the EGR sends back the appropriate signal no code is set. However the EGR passages could be clogged and not allowing the Exhaust gas to be recirculated.
The O2 sensor would adjust the fuel trim to compensate, as long as the fuel trim numbers stay below the threshold no code is set in the ECM for fuel trim either. I would look at the long term and short term fuel trim and see where they are now. You can also go ahead and have the EGR passages on the intake cleaned, it is a simple job. Just remove the intake plastic shroud and the intake cover and look at the passages built in to the cover to see if they are clogged. In my case the hard starting, idle stumbles, and low gas mileage started months before the EGR actually set a code in the ECM. While you have the intake cover off, look for puddles of oil in the intake manifold. You could also have a bad PCV, and oil in the intake is a sure sign it is bad. That is essentially a Vacuum leak and could also cause low gas mileage.
Greg |
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| G. COLTON |
quote:
Originally posted by G. COLTON
More information is needed.
Was the drop sudden or was it gradual? What were the mpgs before and after?
Are you basing your statement on the trip computer or actural calculation of miles driven and gallons used. If based on calculations how many miles/gallons were used to make the calculation.
KDoes there seem to be a difference between open road and city driving?
G
Interesting. I have just had this happen to me and I am in the midst of doing a manual calculation.
G |
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| LoyalMDXer |
I have a 2004 with 18,000 miles and was never impressed with my gas mileage. I average 12-14 mpg in city driving and usually 17-19 mpg on the highway. And yes, the vehicle is mechanically sound.
As far as octane, 91 is what I use.
:28: for gas mileage |
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| eurohazard |
quote:
I have a 2004 with 18,000 miles and was never impressed with my gas mileage. I average 12-14 mpg in city driving and usually 17-19 mpg on the highway. And yes, the vehicle is mechanically sound.
What other car have you had? And what kind of gas mileage did they have?
I am convinced driving habits are the main culprit to low or high gas mileage numbers. I have a 2004 also (16K miles), and I can get 12 MPG also, but that is when I practically race everyone at the stoplights, and have the AC running non-stop. |
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| EXCALIBUR |
quote:
Originally posted by LoyalMDXer
I have a 2004 with 18,000 miles and was never impressed with my gas mileage. I average 12-14 mpg in city driving and usually 17-19 mpg on the highway. And yes, the vehicle is mechanically sound.
As far as octane, 91 is what I use.
:28: for gas mileage
That would be about par for the course with the Acura MDX. It's a mid-sized SUV. If you wanted better gas mileage, perhaps you should've bought a hybrid. |
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| Fireblade6 |
Intriguing post. Since I received my MDX back from the Body Shop after the accident, my MPH dropped from 17.6MPG average to 14.6MPG.
I have some outstanding issues still I need to deal with the service department on things that were not fixed properly after the body shop....
So I will investigate further.
It is interesting that the EGR is going bad... |
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| LoyalMDXer |
quote:
What other car have you had? And what kind of gas mileage did they have?
I am convinced driving habits are the main culprit to low or high gas mileage numbers. I have a 2004 also (16K miles), and I can get 12 MPG also, but that is when I practically race everyone at the stoplights, and have the AC running non-stop.
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Hey, great analogy. I'll bet if you drove it like the space shuttle, you would get even less.......lololol
:1pat: |
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| mdxx3 |
quote:
Originally posted by LoyalMDXer
quote:
Hey, great analogy. I'll bet if you drove it like the space shuttle, you would get even less.......lololol
:1pat:
Hey, we all do this to the wife's car. There's nothing more exciting than hitting 6K RPM and blasting all the junk out of the motor. Shhhhhh.... don't tell any one. :) |
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| Liberty |
Weird. Mine went the other way!!!
My 01 got awesome all-around mpg - about 21-21.5
then, I got the 03 and I was lucky to be getting 13-15:3: as an average (keeping in mind this is 70-80% freeway driving.
Then - boom. At about 35k, my mileage steadily started to improve and now I average about 20mpg. |
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| Neo |
quote:
Originally posted by Gregc
The EGR is a common replacement part and runs around $95 and 2 bolts and 10 minutes to replace.
Greg
Sorry to bump an older thread but is there a writeup somewhere on this?
My MDX has lost MPG lately too. It drives pretty sluggishly and it just had its 60k service. While on a trip, the CE light came on and the local dealer had to do a transmission fluid flush (this is AFTER I had the 60k service done at a local shop) to clear the light. Because we were away, we basically bent over for this one. :(
Anyway, no code showed up for the EGR so the dealership did nothing there. If this really is a $95 item and will take 10 minutes of my time, I am willing to try this out since the dealer will do nothing at this point.
Thanks for any help. |
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