Poor MPG - Low Mileage and hitting 16.7 MPG on HWY

S

SilverStreakFX

Member
Location
San Francisco Bay Area
Car
2010 Fx50s
I have a 2005 FX35, 59K Miles. I am getting consistently 16.7 MPG on the highway.

I think it is too early to replace plugs. Air filter is K&N and clean/oiled.

I use Premium (91 Octane) fuel which I know only takes care of knock, but it is quality gas.

Seafoamed the intake and the fuel system.

I was going to clean the Throttle Body however a TB issue would cause slow response, idle issues, not poor fuel economy.

Any thoughts?
 
If you done some very spirited runs with the car you know it will kill the MPG right? That's why I ask if that a running average or you reset it after a fill up.
 
Yeah, if that's the number off of the computer then it may not be the most accurate. Best to do a manual calculation with your trip meter after a fill up.
 
I have a FX45 and can go from 20-22 mpg highway to 15-16 mpg highway, depending on how bad the wind is. Where I typically drive, it's open fields so has a big impact on fuel economy.
 
I reset each time. It was great on my 07 G. It kept a running total of the resets of something like the last 7 times it reset. Averages 21 MPG.

I will work on manually calculating to see if it is truly an issue or just a computer problem.

Thanks
 
I see you are in the bay area...hills add to your MPG decline, as well as traffic. Try using your cruise control more often. Also I notice better MPG when I accelerate to the wanted speed and then set the cruise control. Mind you, I don't mean WOT until you get to your desired speed but give it some then let off at the desired speed. The slower you go until desired speed, the more fuel your car drinks...at least thats what I noticed.
 
Update

I actually live in the east bay (Dublin, San Ramon) so relatively flat here

I drove 300 miles and filled up with 18.3 gallons. Makes my MPG is 16.4. Computer actually showed 16.9. I made sure not to drive to aggressively so I am really scratching my head why I am getting so low MPG
 
I filled up this afternoon and I had driven mostly highway, and it averaged out to 21mph since my last fill up. I usually average 18-19mph though. 16 is kinda on the low end, at least it would be for me.
 
^ yeah. I heard those fords don't do well in the MPG area. Parking is a pain too ;). Am I too much on your FXless case Lance?

16-17 seems ok. The FX is alot heavier then the G

---------- Post added at 11:07 PM ---------- Previous post was at 11:05 PM ----------

C'mon will. I thought id get away with just the (^) instead of quoting Lance
 
My Bad...

cockblock-army_display.gif
 
sir21 said:
^ yeah. I heard those fords don't do well in the MPG area. Parking is a pain too ;). Am I too much on your FXless case Lance?

16-17 seems ok. The FX is alot heavier then the G

---------- Post added at 11:07 PM ---------- Previous post was at 11:05 PM ----------

C'mon will. I thought id get away with just the (^) instead of quoting Lance
Click to expand...

Man, I don't even check the van mileage, it costs $135.00 to fill it up...I just close my eyes. And parking that shits is just crazy. You pull up to a spot and think ok, I have this, and no, you don't. Reminds of when I borrowed my same friends expedition back in the day. Thing was so long I swear I'd park that thing and the ass end would show up 20 seconds later.
 
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