Lower MPG

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280
Location
Central Texas
Thread starter
2013 Fiesta SE Hatch Manual Trans 1.6 Liter Engine 55,000 miles. Bought brand new. The odometer has consistently reported 37 MPG overall mileage until lately. It is now showing 35 MPG overall MPG for the last several months. Seems a little early for spark plugs. No fuel in the oil. Hardly measurable oil usage between oil changes that I do my self. Mobil 1 From the first time I changed oil. Next oil change is due in several hundred miles. Oil analysis always come back very good. I plan to check the compression at next oil change. I do suspect gasoline quality is heading south in Texas (Shell Regular) - I drove up to Kansas and out west to the Pacific coast last year. Car ran better on gas once I was going west. Even in California. As I entered Texas on the way back I got less pep and poorer MPG. Anything else I should check?
 
Messages
280
Location
Central Texas
Thread starter
I have been through 7 winter blend cycles here (if there is one here) and consistently got 37MPG overall - all seasons, until recently.
 
Messages
599
Location
Ontario, Canada
Try a fuel system cleaner such as Amsoil additive, or techron....and bump it up a grade while running it. Tire pressure also, with temp change tires tend to deflate a bit.
 
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1,555
Location
Americus, GA
Is your clutch slipping? At 55,000 miles that is possible. Seasonal gas blends can make a difference. What is the ethanol content of the fuel that you have been using?
 
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Messages
280
Location
Central Texas
Thread starter
Originally Posted by CARJ
Did you get new tires and/or have you checked your pressures recently?
New tires a year ago. Pressure is on spec.
 
Messages
1,154
Location
USA
Originally Posted by borgward
Anything else I should check?
I'm thinking sticking brake caliper or bad wheel bearing?
 
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Messages
280
Location
Central Texas
Thread starter
Weak Battery could be so. It's as old as the car. Was planning on replacing before the weather gets really cold. Seems OK. All I have to do is bump the starter and the engine fires right up. Never have to crank it, but will check it out.
 
Messages
280
Location
Central Texas
Thread starter
Yeah, The alternator needs to work harder to keep the battery charged, so the alternator puts more drag on the engine for longer periods of time. Might be an esoteric issue on my Fiesta, but on bigger cars with many things running on electricity, electric water pumps, electric power steering, etc, it really does become an issue.
 
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9,356
Location
Canuck living in California
Co
Originally Posted by AC1DD
Originally Posted by borgward
Anything else I should check?
I'm thinking sticking brake caliper or bad wheel bearing?
I will second checking brakes for a dragging caliper or stuck pins.
 
Messages
921
Location
D/FW Metroplex
Originally Posted by borgward
2013 Fiesta SE Hatch Manual Trans 1.6 Liter Engine 55,000 miles. Bought brand new. The odometer has consistently reported 37 MPG overall mileage until lately. It is now showing 35 MPG overall MPG for the last several months. Seems a little early for spark plugs. No fuel in the oil. Hardly measurable oil usage between oil changes that I do my self. Mobil 1 From the first time I changed oil. Next oil change is due in several hundred miles. Oil analysis always come back very good. I plan to check the compression at next oil change. I do suspect gasoline quality is heading south in Texas (Shell Regular) - I drove up to Kansas and out west to the Pacific coast last year. Car ran better on gas once I was going west. Even in California. As I entered Texas on the way back I got less pep and poorer MPG. Anything else I should check?
If you are truly worried that the vehicle is now operating in a less efficient manner, you need to gather more reliable data and then make the determination of whether or not to look for a reason. 2 MPG difference on the stock MPG meter could be attributed to a dozen different reasons, none of which necessarily mean the vehicle is actually using more gasoline per mile. It's your time and effort, use as you wish, but if you have other projects around the house you're putting off to find the culprit here, I'd put this one on hold and do the other stuff, personally.
 
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