I have a 2000 7.3 PSD, the last few weeks I have been seeing a drop in mileage, I used to get 16mpg at least, the other day I got like 6mpg. The truck has a bullydog flip-chip, always set on low, full 4in exhaust, and magnum force intake. I have cleaned the air filter, and checked tire pressure. engine has 82,000 miles on it. SOmeone told me something about a water seperator??? Anyone have any other ideas? thanks

 

I've found that if I change my fuel filter with every oil change that my mileage goes up 2-3 MPG. You can see the slight difference between the oil changes. I thought that my friend was nuts when he told me that I should do this, especially with the price of the filters, but I did see a difference. In my opinion it is worth the cost of the filter and the time just to know that I won't have garbage getting into my fuel injectors and the mileage is a bonus. This may not be your problem, but thats where I would start.

 

ok thanks, its actually about time for it to get an oil change. Any specific type of oil? I think it has like pensoil 5w40 in there right now. I bought the truck used, but I've never changed the fuel filter in it. where is it located?

 

I actually use Rotella 15W40 that I get at the local Walmart. The filter will be a Motorcraft 1995 I believe and should take 15 quarts of oil. The fuel filter is under the black plastic shroud in the center on the engine on the very top. There is a water seperator drain on the passengers side bottom of the filter housing, and if you follow the line down it will empty underneath the truck. I attached a hose to mine after the first time of making a huge mess just draining it. After you drain it just unscrew the round cover that is under the shroud and you will find your filter. make sure that the o-ring on the bottom of the filter comes out with it as sometimes the filter will come out and not the o-ring.
I have also started running Deisel Kleen in with the fuel and it also increased my mileage and at the same time increased the performance of the truck bigtime. I've learned all of this stuff from members of this forum as I'm fairly new to the PSD also. My suggestion is that if you have a question on anything to try a search of the forum first and if you can't find an answer just ask. You will be surprised on the knowledge available here.
Good luck.

 

Check the dip stick after 13 quarts Sometimes that is all it will take and you dont want to overfill it