New to me 7.3

[thegrouse]

I just purchased a used 2000 7.3 powerstroke with 143K. This is my third 7.3 but I sold the first 2 before I got to 50k. I took the truck out for its' first road trip today. I only got 13.3 mpg. This was all on the highway and I figured in the oversized tires. I do not know much about the history of this truck. It appears to have a 4" exhaust that is aftermarket. I just changed the oil and fuel filter once we got back in town. The air filter appears to be brand new. I was really hoping to get 17mpg on this truck. The air filter appears to be the stock Ford box. I have not had a diesel in 9 years and it felt great to hear the motor purr today. I got tired of towing a travel trailer and a tractor behind my F-150. The vehicle is a crew cab 4x4. Any ideas on what I can do to work on the MPG. I hate to put in a chip if it is going to give me transmission problems. This truck has the auto transmission. Thanks

[AOx4]

13.3 is kinda normal... You can get a chip, but it wont help much on MPG.

[Snowman269]

yes, I agree, your mileage is poor. Driving conditions, flatland vs. Hills, driving against a strong wind, bad fuel quality can easily ruin mileage and cause disappointment. A programmer or chip will help, the trans won't suffer unless you drive it hard, and that kills fuel economy anyway.

I wouldn't worry about mileage yet, but if it doesn't improve, then I'd start modding. All trucks aren't the same, I have one truck that clearly gets significantly better mileage towing than all the rest. Everything gets 10.1MPG towing a trailer at 70mph, except 1, and it gets 14.1mpg. I have had it for years, and I won't get rid of it, it is just special or different, & I can't figure out how it does so much better than the rest, cause I'd change the others too, it's just a good one.

[ken6881]

i get 18+ regularly in mine there a few threads about cleaning the ebp tube and sensor and a few other things to help with mpg. Also run some Diesel Kleen through it can help.

[thegrouse]

I am going to check the first few tanks to get a better idea on mpg. I made sure I filled it all the way to the neck both times. I am going to try to get my diesel at a bigger station also. The trip yesterday was all flat interstate.

[ken6881]

also if your trying to make time running 75-80 your going to get poor millage compared to cruising at 65-60. 3+ mpg difference on my truck

[85_305]

Originally Posted by ken6881

i get 18+ regularly in mine there a few threads about cleaning the ebp tube and sensor and a few other things to help with mpg. Also run some Diesel Kleen through it can help.

Agreed... diesel kleen gets me 2-3mpg better EVERY tank.

Originally Posted by ken6881

also if your trying to make time running 75-80 your going to get poor millage compared to cruising at 65-60. 3+ mpg difference on my truck

Agreed that driving too fast will kill you.


OP, what condition is fuel filter in? Do you run additives like DK? You should be.

Also, what size tires do you have? Keep in mind if the speedo hasn't been corrected, your mileage will be off. My mileage is off 5% w/ 35's...

[thegrouse]

I changed the fuel filter yesterday but the one that was in there didn't look too bad. The tires are a 315/75/16. I measured out 10 miles on the interstate using the mile markers. The truck odometer showed 9.3 miles. Using this formula I figured the miles I drove on a tank were 93% of actual miles. The 13.3 was calculated using this info. It probably would have been 12 mpg had I not corrected for the tires. I have not used any diesel kleen or additive. If I can get 2mpg better it may be worth a shot. The speed limit is 70 on the interstate and I wasn't doing much more than that. I am not sure how far off the speedo is though.

[ken6881]

I work for a highway department I would not trust those mile markers. One could be a half mile off and would not be uncommon

[thegrouse]

Ok. Maybe it wasn't as scientific as I thought. I may try GPS next time to get a better reading.