I used to get about 15 MPG on average with my 1997 f-150 with a 4.6 liter engine, and 3.55 rear end. it has slowely gotten worse, and now i'm only getting about 12 MPG. can anyone tell me why?

 

lead foot

 

The best I got for city mpg was 12.9 and highway 15.6. Read my sig to see what I have. Of course I have a lead foot most of the time.

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1997 XLT Teal 4.6L Flareside 4x4 ORP. Automatic, Reg. cab, 3.55LS, tinted windows, bug deflector, Dual exhaust, K&N Generation 2 air filter, BullDog keyless entry/remote start, Modern 16" wheels, bedliner, Covercraft tonneau cover, White faced gauges, electronic shift on the fly, Clarion ADX5655z Double Din Cassette & CD, 4 Pioneer TS-A6865 speakers and superchip. Going to add headers.




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Have you been keeping up with your scheduled maintenance?

Have you noticed a corresponding loss of performance while your mileage has been going down?

I'm thinking your problem could be something as simple as a clogged air filter.

If you haven't had a loss of power, how has your engine temperature been? Cooler than normal? Could mean a thermostat stuck open causing the truck to take a longer time to warm up which will keep it running rich for a longer time.

How is the fuel in your community? It could be your area runs special winter fuel which has less btu content which means you need to burn more.

Hope the above gives you some ideas of where to start looking.

 

Have a 97 F-150 SC 4X4 4.6L with 53,000 miles on it. I bought it with 36,000 miles last May. I got 16.5 mpg thru the summer and fall but when winter hit it dropped down to 14.5-15 mpg. Now that warm weather is here I am back up to 16.5 mpg.
One thing I just figured out was when I used the heater/defroster the compressor comes on. I now try to use only the vent with the heat **** adjusted to the temp I am comfortable with.
I stay away from the re-formulated gas and always try to get to an Amoco station.

 

Sounds about the same mileage I get. I got used to it.

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black 97' x-cab 4x4, 5 speed 4.6, black westin nerf bars, pilot ground searchers, borla SS split rear exhaust, K&N genII, bosch +4 plugs, flexalite electric fan, v-tech oval side window covers, IAS shocks

premier 720, pioneer 6cd changer, 12 premier sub, premier componets, 2 soso amps

This truck is for sale.
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