Wtf...... 6.5 Mpg?

[lsdarkshadow]

So my car (2001 V8)(106,342) is only getting 6.5 MPG. I never drive it on the highway but it should still be alot higher. How is this even possible. The only engine mod I have is a true cold air intake set up from Japan. (I have an enclosed cone with direct airflow from under the car and it's 40 degrees outside. That's cold.) All new spark plugs and coils went in early this summer.

Any idea's?

 

[Outkast]

fill up, hit reset, and try again...

if there is no raw fuel pouring out of your tailpipes, I'd say its a malfunction.

the comp is not always accurate.

 

[Quik LS]

un-hook the battery for 10mins - which will reset all that. after about three tank fulls you should see what it really is - unless something is actually broken.

 

[joegr]

Is your speedometer correct with those tires? (If their diameter is larger than the stock tires, you will move further than the odometer says, and this will make your (or the message display) mileage calculation come out lower than it really is.)

Otherwise, is the check engine light on?

 

[lsdarkshadow]

un-hook the battery for 10mins - which will reset all that. after about three tank fulls you should see what it really is - unless something is actually broken.

Just out of curiosity, what type of mechanical problems could cause heavy fuel consumption, or is electrical more likely a culprit.

 

[lsdarkshadow]

Is your speedometer correct with those tires? (If their diameter is larger than the stock tires, you will move further than the odometer says, and this will make your (or the message display) mileage calculation come out lower than it really is.)

Otherwise, is the check engine light on?

No engine light. The tire size should be correct. 245/35- 19. I hvae heard of the problem when people run the 20's with too big a tire, but my low profile 19's should be on the money. They stood right up next to my 17's and appeared close.

 

[BrianDye]

Mine was saying 14-15 mpg on the HIGHWAY ride home, pressed RESET, and boom, right up to 19-20

 

[NYC LS8]

When was the last time the fuel filter was replaced?

 

[joegr]

Mine was saying 14-15 mpg on the HIGHWAY ride home, pressed RESET, and boom, right up to 19-20

Just so you know...

The mileage readout on the LS is the average of the mileages that you have gotten for the last 1500 miles or so. When you hit reset, you will give the mileage reading for what you are doing right at that moment, and then restart the whole 1500 mile average. The 1500 mile average is a lot more useful than the instant mileage because it shows what you are getting on average.

I had a Grand Marquis that had both average and instantaneous readouts. The instantaneous readout would show 1 to 5 MPG going up a hill, about 20 on even ground, and 99.9 MPG going down a hill. (It actually did better than 99.9 down a hill, that's just the highest it could display.)

 

[Outkast]

Just so you know...

The mileage readout on the LS is the average of the mileages that you have gotten for the last 1500 miles or so. When you hit reset, you will give the mileage reading for what you are doing right at that moment, and then restart the whole 1500 mile average. The 1500 mile average is a lot more useful than the instant mileage because it shows what you are getting on average.

I had a Grand Marquis that had both average and instantaneous readouts. The instantaneous readout would show 1 to 5 MPG going up a hill, about 20 on even ground, and 99.9 MPG going down a hill. (It actually did better than 99.9 down a hill, that's just the highest it could display.)

my freightliners and peterbilts do the same thing...plus ECM will show lifetime avg.

 

[PetesSweets86]

your MAF could be f*cked, but that's a guess

 

[1LoudLS]

i would check the mpg the old school way, fill the tank up, reset the ODO, drive for a couple of days, then fill it back up, then divide miles driven by gallons of gas used, if your actually getting that low of millage then something is terribly wrong.

 

[ToeCutter]

:I ...do not put your faith into such machines of deceit.... i.e. the computer

 

[Lincoln Jealous]

you have to reset it again, after you do alittle better driving, but if all you do it stop and go, i dont doubt it, just hit reset after you do alittle more driving

 

[Alexbougie]

your MAF could be f*cked, but that's a guess

If MAF is :q:q:q:qed he should Have a Check Engine Light but but he doesn't :shifty:

 

[PetesSweets86]

like I said Alexandra....I was throwing out a guess....dirty MAFs can often f*k up the mpg...so I've heard

 

[owlman]

Just turn off the display and enjoy life.

 

[Alexbougie]

Just turn off the display and enjoy life.

+1

 

[Lincoln Jealous]

like I said Alexandra....I was throwing out a guess....dirty MAFs can often f*k up the mpg...so I've heard

no guesses, or hear say please

 

[cmack]

Are you putting gas in more often now, than say a few months/year ago?

 

[lsdarkshadow]

wow, alot of reponses. I gotta stop going to work.

No on the fuel filter, but how would that afect MPG? Also I have noticed a slight slugishness on the acceleration. Just slight.

 

[drag214]

wow, alot of reponses. I gotta stop going to work.

No on the fuel filter, but how would that afect MPG? Also I have noticed a slight slugishness on the acceleration. Just slight.

Your fuel filter should be changed every 30,000 miles. That could cause your slugish acceleration. I don't see that causing the low MPG average. I'll do some research and get back to you.

 

[joegr]

Your fuel filter should be changed every 30,000 miles. That could cause your slugish acceleration. I don't see that causing the low MPG average. I'll do some research and get back to you.

I'd like to add a little bit to this point.
The LS uses a returnless fuel system. Fuel pressure is regulated by measuring fuel pressure at the fuel rail (past the filter) and then running the fuel pump at whatever power level is required the maintain the correct pressure. This means that if the fuel filter is clogged, the fuel pump has to be run at a higher power level, which means it won't last as long as it might otherwise.