2003 7.3 Fuel Milage SUCKS

RichieRich · Mar 1, 2013

ok, so I just got this truck a week ago and filled it up full after an air filter, oil filter and fuel filter change...I went last night to fill it up again as I am heading camping this weekend and the miles I had driven last week were 158.6 and I filled it up at a little over 16 gallons last night. Does this sound right? only getting less than 10MPG. most of the driving has been around town with little to no freeway, and it is running 285 75 16 tires. I believe it has 3.73 gears, but I am not sure. When i brought it home it had a hell of a diesel leak out of the petcock, that was fixed i thought until this morning I notice a small silver dollar sized drip on the concrete under the truck. It looks like oil, but really didnt have time to look at it since I was on my way to work. What is a realistic fuel milage for this truck? Also, what are some of the things I can check out to be the problem. BTW I am comparing this to my 2003 Duramax that would get about 22-24 highway.

Freightshaker · Mar 1, 2013

Research cleaning the ebpv. The one on my truck was packed solid. My 01 is stock and does 12-13. I still think it's low and plan on to continue addressing it. I'm not worried about it burning a hole in my wallet, it's a heavy truck. My biggest concern is just making sure everything is functioning the way it should and I'm still learning.

RichieRich · Mar 1, 2013

I agree with that Freightshaker, its not a Prius! But I just want to make sure I am doing everything I can to keep this truck happy as I plan on keeping it a long while

yzrmbsg · Mar 1, 2013

Clean ebpc tube and sensor, replace both if necessary. Rebuild the fuel bowl, orings, compression gaskets, ariund $20 at riffraff or diesel orings. If you can, check fuel pressure. Check for brake drag, very common problem in our trucks. Check air pressure in tires. Keep control of the skinny pedal, try to keep it under 2000rpm's and below 600º egt's. All that and 35's on mine and I am getting between 13-15mpg, depending on if people wanna try and cut me off in traffic! I also just installed a tonneau cover tonight, so that should help me out a little bit. I don't expect to get better than 15mpg, I've heard its possible....but can't expect too much for such a pig!

Jason · Mar 2, 2013

Boy you people are getting some terrible mpg from your trucks.

yzrmbsg · Mar 2, 2013

Jason said:
Boy you people are getting some terrible mpg from your trucks.

Want to elaborate please?????

littleredstroker · Mar 2, 2013

yzrmbsg said:
Clean ebpc tube and sensor, replace both if necessary. Rebuild the fuel bowl, orings, compression gaskets, ariund $20 at riffraff or diesel orings. If you can, check fuel pressure. Check for brake drag, very common problem in our trucks. Check air pressure in tires. Keep control of the skinny pedal, try to keep it under 2000rpm's and below 600º egt's. All that and 35's on mine and I am getting between 13-15mpg, depending on if people wanna try and cut me off in traffic! I also just installed a tonneau cover tonight, so that should help me out a little bit. I don't expect to get better than 15mpg, I've heard its possible....but can't expect too much for such a pig!

I can't run 65 on my eco tune under 600*..

sent while trying not to JJ My rods!!!!!!

Jason · Mar 2, 2013

What needs elaboration?? 13-15 isn't great by any means..it's "decent". Hell, I got 13.66 mpg coming out of New Mexico back home with my 24' enckosed car trailer in tow with a 3500lb car in it. Keeping rpm below 2k when accelerating (yes, it is slower than shti doing it this way, but it works), and setting the cruise at 71mph (1950 rpm), running Gearhead tunes, using the cruise to pull me along if I got slowed down etc. That was my '02 ccsb 4wd with 305/60/18's, 4" mbrp turbo back with muffler, 6637 filter, and running Matt's tow tune. Also had an aftermarket tranny too.

My '00 in my sig is at 409 miles and still has a 1/4 tank left. Regular cab longbed, STOCK on factory sized tires. Same tactics, keeping rpm low, not flooring it for passing gear, but using overdrive to pull you along. Learning how to work your right foot can do wonders. Truck has a 4" turbo back and thats it.

This isn't off a lie-o-meter etc. either, it's hand calculated miles, speed is off the gps, miles are tracked gps vs the trip meter. I don't try to get good mileage, I am not one of those guys who really worries about it, but years in the trucking industry has taught me light foot, low rpm, don't crowd the motor and let it do its deal.

Jason · Mar 2, 2013

***, my '09 gt in my sig goes bottom 12's as it sits in the quarter mile, and gets 24mpg with the cruise at 75. And I am not always nice to that car...i dontrag it out, but I drive it spiritedly. Just so you don't think I am some hyper miler bs'er etc..my Yukon Denali gets 14 on the highway all day long. No matter what you do, so piss on it, something you live with.

yzrmbsg · Mar 2, 2013

Guess it didn't need any more elaboration since i'm not doing much if at all different from you. Best I have seen was 15.6mpg. I thought you had good news....I wonder whats so different between lower mpg trucks vs yours....

RichieRich · Mar 3, 2013

Yesterday I shut the truck off right after towing and got a P1069 code...something to do with the waste gate. I wonder if that has something to do with it.

PA Stroker · Mar 3, 2013

I get about 10 in my truck on winter fuel. Thats on 35's but the best stock I ever saw with my truck was about 15 or so.

Rupp250 · Mar 3, 2013

Welcome from Glamisdunes.com It's better here then Duramaxforums. I just got back from going to the beach, pulling a 25ft toyhauler, 10k lbs, and my lie-o-meter is showing 11.8. It is usually pretty close to actual mileage though.

yzrmbsg · Mar 3, 2013

Rupp250 said:
Welcome from Glamisdunes.com It's better here then Duramaxforums. I just got back from going to the beach, pulling a 25ft toyhauler, 10k lbs, and my lie-o-meter is showing 11.8. It is usually pretty close to actual mileage though.

I miss Glamis.... :'(

907DAVE · Mar 3, 2013

Plenty of good times there for sure!

Dieselboy. · Mar 3, 2013

Reg cab in my sig gets a consistant 13.5-14mpg of hwy/city/winter warmup/idling.

RichieRich · Mar 3, 2013

What up brother? I recognize your baby from GD.com

I just got back from Johnson Valley where I averaged 10.8 MPG towing my 12,000 lb fifth wheel with a head wind. Not too bad

1ofakind79 · Mar 4, 2013

I get about 9mpg towing 10K and 17mpg empty if I watch how I drive. If I drive like me about 14mpg. Trucks in my sig.

Jason · Mar 4, 2013

Just filled up last night...437 miles on the clock at time of fill up. 238 of that interstate the other 199 in town stop and go, NO highway, just city streets. 25.6 gallons, thats 17.0 mpg. No idea when fuel filters were changed last, all fluids were clean and full when I picked it up, but I will be doing a full fluid/filter change shortly.