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Edgieguy

3.7L Sport MPGs dropping...dropping....dropping

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So my Edge Sport has recently celebrated its 7th year with us and at slightly over 73K miles Ive steadily noticed a decline in my highway cruising mileage. Now the Edge was never a really economical vehicle to begin with, but I managed to average close to 20mpg in mixed daily driving. On a recent 9.5 hour long cruise control trip thats the best I could manage. Those trips almost always netted me 23+ mpg. Ive seen as high as 27mpg. (computer, not calculated). Does anyone have any ideas on what Im missing? I run synthetic oil, proper tire pressure, and my Edge is very well taken care of. Open to all ideas.

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Could be time for a plug change. My 2007 3.5 was down to 17 mpg @ over 100 thou. New plugs and it averaging 19mpg. Also check tire pressure, it can have a dramatic effect. It's winter and your tires are probably on the low side.

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Could be time for a plug change. My 2007 3.5 was down to 17 mpg @ over 100 thou. New plugs and it averaging 19mpg. Also check tire pressure, it can have a dramatic effect. It's winter and your tires are probably on the low side.

Plugs I have not done. I have them, but when I couldnt see the rear set to get to them that project went on hold. Im living south nowadays so Im still in the 70's, but even so I keep up on tire pressures.

 

Was thinking maybe a dirty air flow sensor?

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Possibly a dirty mass air flow sensor. It only takes a small amount of oil grime buildup on the thin heated wire to throw off the air/fuel balance and lower mpg.

https://carcarenewsservice.org/article/clean-mass-air-flow-sensor-restores-lost-mpg-and-horsepower

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Plugs, possibly PCV valve, and transmission fluid at a minimum. Videos on each of these subjects over at macbwt's channel

 

Very worth your while to browse his channel/join his FB page. Questions will be answered on FB only.

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Another possible consideration: any oil in the intake tube? Some MYs are prone to engine oil migration in the tube, and the fix is a new valve cover (the one by the radiator).

 

As far as DIY fears, I remember when you first set out to polish and shine up your Edge. You ended up doing a splendid job. Definitely have skills, so I see no reason to worry.

Edited by WWWPerfA_ZN0W
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seafoam the intakes.

Edited by pinyin

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@WWWPerfA_ZN0W, Good stuff. :love_shower: I missed this video somehow. Im newly motivated to change my plugs, clean my MAF and PCV. Ill report back if I can find my missing MPGs. :shift:

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Keep in mind the winter fuel mix is also in effect and your mileage will drop also.

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Seafoam the intakes or take the throttle body and intake off and clean by hand. The oil that gets into the snorkel and makes it's way into the intake through the throttle body eventually messes with your octane and degrades your mpg's. This takes awhile so it's hard to pinpoint the problem right off the bat. Plugs should not increase or decrease mpg performance, unless you're at the scheduled maintenance interval and should do them anyway. Transmission fluid change has nothing to do with bad mpg unless you're not shifting into 6th at highway speeds, but that would be noticeable. Bad MAF will throw a code.

Edited by vrdublu
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I've been on owners groups and different forums since 1995. Even though my Dad made me a DIY'er, Sometimes I still get stuck for a lack of confidence. My spark plug project was one of these. I'm thankful for all the contributors on forums, but for this project I'm especially thankful for @WWWPerfA_ZN0W. Thanks for the vote of confidence, it took a few months, but last week I had had enough of my procrastinating and stopped at Advanced Auto for some MAF cleaner. It took a while I know...But I got it done.

 

2lw9e6w.jpg

 

Originally, I just purchased some MAF cleaner and planned to just spray out the module. I was soon washing the air box, and cleaning oil out of the air snorkel. I wound up disconnecting and cleaning the throttle body after that. Since I was so far in, I decided to start the plugs. Fronts went quick, the rears not so much...

 

okvmmw.jpg

Edited by Edgieguy
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These plugs at 75K miles have seen better days.

 

33bpjsp.jpg

 

332v3ft.jpg

 

When I was all done, I decided to detail the engine bay...Then change the oil.

 

2hmgdb9.jpg

Edited by Edgieguy
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Wow, you really got it all buttoned up. Nice work! Yeah those were some hard miles on the plugs. There are people with 150K miles on original plugs (yeah, I know) that have less wear LOL.

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I saw a 2.5 MPG increase in my Taurus SHO when one faulty wheel bearing was replaced. I drive a easy, constant speed highway commute everyday, and it was 20.5 MPG before and 23 MPG after. Many tanks of fuel confirm both the before and after MPG change. So a bearing on the way out could eat a MPG or so before you start hearing it. Have a couple doing it (or more) and you could lose a few MPG without hearing a bad bearing yet.

 

Just to show how bad it can get with the bearings- prior to purchasing the Taurus I made the seller take it to the dealer to address road noise I heard on the test drive. They put four new tires and two front wheel bearings in. Once I got it, it still made a little noise and Ford replaced the right rear bearing as I described above (so yes, 3 of 4 bearings replaced at less than 40K miles- pathetic). Anyways, when I got the car from the previous owner, the trip OD and associated avg fuel economy had not been reset for the last 6K miles. They had averaged less than 16 MPG with three bad wheel bearings (with who knows what commute, but they lived out in a rural area so it was probably mostly highway speeds). I now average over 23 MPG.

Edited by IWRBB
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What did you use to detail your engine?

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What's your mpg now?

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So far my mileage has improved somewhat. I really haven't driven enough to get a good read on it. I have a 1994 Toyota MR2 Turbo that I like to cruise around in, and use our golf cart around our development, so the edge doesnt see much use.

 

4uj694.jpg

Edited by Edgieguy
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So I'm curious, how do I determine if i have a bad wheel bearing? My overall mileage has not gone up after the work I did.

 

I saw a 2.5 MPG increase in my Taurus SHO when one faulty wheel bearing was replaced. I drive a easy, constant speed highway commute everyday, and it was 20.5 MPG before and 23 MPG after. Many tanks of fuel confirm both the before and after MPG change. So a bearing on the way out could eat a MPG or so before you start hearing it. Have a couple doing it (or more) and you could lose a few MPG without hearing a bad bearing yet.

 

Just to show how bad it can get with the bearings- prior to purchasing the Taurus I made the seller take it to the dealer to address road noise I heard on the test drive. They put four new tires and two front wheel bearings in. Once I got it, it still made a little noise and Ford replaced the right rear bearing as I described above (so yes, 3 of 4 bearings replaced at less than 40K miles- pathetic). Anyways, when I got the car from the previous owner, the trip OD and associated avg fuel economy had not been reset for the last 6K miles. They had averaged less than 16 MPG with three bad wheel bearings (with who knows what commute, but they lived out in a rural area so it was probably mostly highway speeds). I now average over 23 MPG.

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If you are not hearing a noise while turning, predominantly in one direction vs the other), then likely the wheel bearings are still OK. Yeah you can try spinning the tire/looking for play while the Edge is jacked up/lifted, but that test does not necessarily work with sealed wheel bearings.

 

If you have an AWD, I would suggest to you to look to that next. PTU fluid/RDU fluid replacement are crucial, especially if you are not driving a lot or are driving primarily city/mixed conditions.

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You should hear it. It's going to be a rumble/buzzing type sound that increases with speed in a straight line, or the "wub wub wub" sound as you go around corners.

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Okay. Im going to have to take a ride and really concentrate on the sound of the car. I know I've heard a buzzing once in a while like roughvut pavement, but it also could've been roughcut pavement.I'm not sure if the PTU was ever serviced. I need to look for a How To.

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There is no official "howto" but plenty of people will show you the basics of how they replaced the PTU fluid. the_natrix originally did a writeup on installing a drain plug as well. I think everything is in the "PTU leak / failures" thread.

 

Buck Newby does have PTU related videos on his YT channel, I would check those out.

https://www.youtube.com/user/buckn32

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