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Getting really low gas mileage

1K views 10 replies 5 participants last post by  amustangrocks 
#1 ·
Hi there,

I have a 2007 V6 manual Mustang. It's at about 58k miles and just had it's oil changed. I have a K&N air filter, which is probably the only thing that I've modified on it. I'm trying to figure out why, lately, the gas mileage has plummeted. I mentioned it at my last oil change and they told me it was due to the gas that gets used for winter. I want to call ******** on that because I've had this car for 4, almost 5 years and consistently have gotten 25-28 MPG and am now getting <20, it seemed like it's been decreasing for about the last 6 months or so. I'm not good with cars so I was really hoping someone could give me a few ideas on what I could check out or fix on it.

Thanks in advance,

Danyelle
 
#2 ·
Hi there,

I have a 2007 V6 manual Mustang. It's at about 58k miles and just had it's oil changed. I have a K&N air filter, which is probably the only thing that I've modified on it. I'm trying to figure out why, lately, the gas mileage has plummeted. I mentioned it at my last oil change and they told me it was due to the gas that gets used for winter. I want to call ******** on that because I've had this car for 4, almost 5 years and consistently have gotten 25-28 MPG and am now getting <20, it seemed like it's been decreasing for about the last 6 months or so. I'm not good with cars so I was really hoping someone could give me a few ideas on what I could check out or fix on it.

Thanks in advance,

Danyelle
Hi
I'm no expert by no means but Ive just had a similer experience to a small degree. I have a stock 05 GT and about 3 months ago I had the money so I did a complete 100k service at Ford, (Spark plugs, etc)> When I got it back I was certain my Gas Milage had gone for a Crapper (Weekly refill down to 3-4 days). I tried the different gas, filter, etc but still the same. Anyway, about 3 weeks ago I messed around trying to install a Tune through my 2nd hand SCT tuner. Damn car wouldnt start so I disconnected the Battery for about 40min and finally reinstalled the Stock tune that the Tuner had saved from my original program. Boom!!, I'm back to weekly refills on gas. I swear it had something to do with resetting the Computer through battery disconnect, (I think Ford screwed me during the service)
Anyway, just a strange story but thought I would share it..
 
#3 ·
welcome to the forums. i used to fish portage lake when i was younger (many years ago). i know its cold there right now, if your letting your car sit and warm up it kills the mileage. its cold here at nights, so ive been letting it get warm in the mornings, and my mileage is down too.

also the fuel is worse, winter additives, ethanol ect. that doesnt help. you should be on your 2nd fuel filter about now, and replaced the plugs already. if your throttle body has never been cleaned, its likely needing to be cleaned. between now and the next 40-50k, your into some routine maintenance items.
 
#4 ·
The weather is actually not too bad here right now. It's only snowed 2-3 times and it hasn't stuck, looking at an unusually warm, brown Christmas at the moment. I don't let it get warm in the mornings either, I usually forget. Hahah.

2nd fuel filter about now, and replaced the plugs already.
I definitely think I'm going to have to look into that one, because this might be the case. And I don't think I know anything about the throttle body.
Should I just take it back to the dealer to get these things worked on/fixed?
 
#5 ·
if you can diy, you`ll save a lot of cash. i would highly recommend buying the chilton manual for 20-25.00, lots of good info.

spark plugs, simple enough, use some anti-seize on the threads when you install them.

fuel filter is under the plastic panel, under the drivers seat(under the car). i just remove the fastners and let the panel hang down where i can see and get to the filter. lay a towel on the panel to catch the spill. its a good idea to pull the fuel pump relay in the fuse box under the hood. its the first row, middle relay towards the battery. crank the car over a couple times, it might try to start, thats ok. this will relieve any pressure in the system. loosen the clamp holding the filter, push the green tab in while pulling the hose connector off the rear( might have to push the filter forward a little) then do the same for the frt connector pushing the filter back. make sure its in the right direction and that the connectors click good re installing.

buy a spray can of throttle body cleaner. remove the intake tube from the tb. remove the 2 wire connectors by pulling the red tabs forward and pressing the exposed part of the plug and pull them off. theres 4 small bolts holding the tb on. once its loose, there s 2 coolant lines on the bottom. i would highly suggest bi passing them. i think i took the longer hose off, turned it around and made the bi pass, you can see it in this pic
http://www.allfordmustangs.com/foru...stang-t-b-coolant-pass-review.html?highlight=
with the tb off( dont remove the black parts on the sides of the tb( pass side is the tb motor, driv side in the tps sensor) spray it real good and wipe it out with a clean cloth till its shiny again. make sure the oring gasket on the engine is ok and re install everything.
 
#6 ·
I currently have the same issue with my pony. It's gone from weekly fill ups to filling up every 3 days. I get my oil and filter changed every 5 to 7 thousand miles and im about due for my next change. My car has 81,250 miles on it. Can you advise on what else I may need to do so i got back to my weekly fill ups.
 
#7 ·
does having the BAMA 93 octane race tune hurt your MPG too?
 
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