MPG City/MPG highway

[zecolleman]

ok this is my problem.I own 2004 Explorer 4.6 V8 with 60000 milage on it. I filled up my gas tank and drove 120 miles in my town (all short distance) and fill it up again shortly after the low fuel warning came on 18 gallon. So 120 mills on 18 gallon it makes 6.6 mpg NOT GOOD. And the strange thing about this is that the car is fine on the highway. 21 MPG. I have allready change plugs, fuel filter and air fillter and I am going to clean the throttle body and check on Fuel Pressure Regulator, but I think that is not the case. It is somthing bigger, This is ridiculous milage...Hope you have some ideas because I love everything else about this car.

 

[Merc02]

So, you filled up with 18 gallons after the warning? Was the needle reading low too? The warning usually comes on when it calculates that you have 50 miles before empty.
Maybe something is added to the fuel in Iceland that is lowering your MPG.

 

[zecolleman]

no I don´t think so like I said the highway mpg is very good.

 

[jaydez]

Do you take off from stops like John Force or grandma in an 84 Topaz?

No matter what the car or the condition if you floor it off every light you will get horrible gas milage. My Ex averages around 18-19 MPG with mixed driving. If I run just highway under 70 MPH I can see 22+ MPG out of the display. As soon as I hit stop and go traffic off the highway it plummets down under 19 MPG.

If you drive reasonable, try the simple things first. Change the spark plugs and fuel filter and see where it goes from there.

 

[zecolleman]

This example I took was based on as much efficient driving as I can.

 

[jrford]

Whats the temps like in iceland? I'd fill up run a tank or two and see what you get.
vacuum leak maybe? One trick to find these is take a can of Carb cleaner and spray down the vacuum hoses, Id try to be safe about the chit is flammable, i only do it on a very cold engine away from sparks etc yada, yada. Once the cleaner hits a leak the RPM's will bump up indicating the leaking hose or joint. . .
just an idea to try maybe?

With ours when Mrs. Leadfoot is driving, shes gets about 13mpg city/hwy mix (using the truck computer). For a few years she had a short commute of 2 miles with about 4 lights, and never faster than 45mph, she got 9-10mpg during winter (10-30F), truck never had a chance to warm up. Now its more like 14mpg with her 25mile commute during winter, 16mpg summer.

 

[zecolleman]

Temp was maybe 50-60 F at this examble. If it was a leaking vacuum would it not effect the highway driving to? That is what I find strange what the diffrence is much. My frend drives v6 and is geting a litle worse milage then me on the highway but much much better in the same town as I with very similar driving.

 

[jrford]

good question, not sure. Its just that any leaks in the system, confuses the computer and O2 sensors, with a vacuum leak there is more air is getting in so it compensates by dumping more fuel, they also cause rough idle to so . . .just an idea.

Another idea is the MAF sensor, has it been cleaned? How did the plugs look? Regretfully, there are a few systems on this thing. . .you probably don't have a scan tool where you can monitor stuff in real time? Or a shop?

 

[zecolleman]

Yes the MAF sensor is good I cleaned it and it looks good. I ongly have scan tool to see if there is any error code. I actually bought OBD-II OBD2 Car Code Reader USB Interface EOBD CAN-BUS http://cgi.ebay.com/ebaymotors/ws/e...0401756768&viewitem=&sspagename=STRK:MEWAX:IT but I can not seem to get to work. maby softwere problem or something.

 

[jrford]

They say in the ad
'Read diagnostic trouble codes, both generic and manufacturer-specific, and display their meaning (over 3000 generic code definitions in the database).' for $12?

What they are trying to say Ford Enhanced Codes, Over here in the states that used to be expensive - $1,000's of dollars to get the reader to do it. Search on Ford Diag tools to see. these be the bomb - 'FORD WDS FACTORY SCAN TOOL' or 'FORD ROTUNDA NGS'

Recently some have written software to do it to, but that still $100's of dollars.

Not sure what different up in Iceland but this is new to me 'European On-Board Diagnostics' might apply to the European built cars/trucks? With the Ex i'd almost guess its OBDII since it only built in the states.
Not sure who you could ask. . .

What i use is laptop software.
http://www.bowserelectronics.com/
In the package he sells the harness to plug into the ODBII connector and software that you run on a laptop. i've bought it and it does work, fixed ABS sensors, parking sensors and it reads all of the 'Enhanced' codes. I paid like $230 for it.

 

[zecolleman]

Thanks I wiil download your softwere and try it. I can´t do it right away becose my laptop just crased but I will post and tell you if it worked...I hope it dose and I can find the problem, I realy love this car but it will forse me to sell if I dont find this I can not afford this much gas fore long :-/