Newbie New with trouble

[1800thehill]

I have a 99 F-250 with a 7.3 and 286k. I've had it for three years and it has and still runs perfect. It has averaged about 19 mpg until recently, when it suddenly dropped to about 14 mpg. Smell like it's running a little rich. Does anyone have any suggestions?

 

[DaveBen]

Your filters, especially the air filter. Also Winter Diesel is not as good for mileage as Summer Blend. About 10% less in Winter.

Dave

 

[bears4x4]

I have a 99 F-250 with a 7.3 and 286k. I've had it for three years and it has and still runs perfect. It has averaged about 19 mpg until recently, when it suddenly dropped to about 14 mpg. Smell like it's running a little rich. Does anyone have any suggestions?

do what dave says ,
and its cool to see another upper milege 7.3 sd out there runnin good.

 

[atk]

Welcome to SDD....

 

[WD40]

Welcome to SSD.com, always good to have another Razorback here. Hope you come back often.
Doug

 

[JLDickmon]

I have a 99 F-250 with a 7.3 and 286k. I've had it for three years and it has and still runs perfect. It has averaged about 19 mpg until recently, when it suddenly dropped to about 14 mpg. Smell like it's running a little rich. Does anyone have any suggestions?

Welcome to SDD.com
do what Dave says.. change all the filters..
the recent cold snap has a lot to do with it, too..
might not hurt to run some Seafoam through it for a couple tanks..

 

[wpecjak]

Filters always a good idea. But what is Seafoam?

 

[1800thehill]

Thanks

Thanks for all the info. I will probably get to know you guy well in the coming months. I'm going to try and fix this truck up some. Thanks again.

 

[JRJ04]

with that kind of mileage, you could be due to rebuild your injectors, or at a bare minimum replace the o-rings.

 

[CHPMustang]

On your next oil change run a Oil Analysis as it'll reveal how far gone your injector o-rings are amongst other wear items within the engine

One things for sure the Diesel engine needs heat to burn the fuel completely but with a cooler engine and fuel it's just not going to burn all the way which will result in lower mpgs for sure.

Upgrading the coolant thermostat with a 203 degree thermo will help and will also throw out much hotter vent temps

DIESELSITE 203* Thermostat
Black Billet Aluminum Thermostat Housing