Just completed my 11,768 mile round trip (long a$$ed drive alone) for the summer. Northbound managed a best of 23.41 mpg. Southbound it flirted with 20.5 to 21.5 mpg at 65 mph. Near the end I decided to try 59 mph for 300 miles and ended up with only 22.8. Now why did I do better northbound in cooler weather and at about 64 mph? All fillups were done very carefully some taking as long as 10 minutes after the auto shut off. Added the straight 4" turbo back while in Fairbanks. Could this have cost me mpg? Is my 6637 dirty and I don't even know it? I ordered a new one from Fleet today, but I doubt that is the problem. Need some opinions here. How can a better exhaust system lose me almost 1 mpg? Is something hidden going wrong? Thanx y'all. Gotta work on that now that I am back in the south.

 

hmmm, its hard to say if "everyone" is acurate with thier averages. This guy at work has this rediculous thing about chevy vs ford, and how chevy is a real mans truck and he gets 200000mpg towing 70k lbs. I guess you are not a real man unless your truck gets insane mpg #'s. I was getting 8mpg towing to tahoe (2000 psd, rwd, 6in lift, 18's w/33's crewcab, 4in turbo back exhaust, K&N, and hypertech stage 1 towing programm) I wanted to jump out and push at those avg's especially in cali $3.03 gal, Tahoe fuel was $3.39 ouch, I saw my mileage jump to about 11mpg in stage 2 on the way back. It is what it is, if I tell the guy at work what mileage I got he will declare Chevy as the best (we all make fun of him for being a dumbarse) .......I think if I change my fuel filter it will help alot, for now it sux.

 

My '02 4x4 PSD gets roughly 14-15 in town and about 18-19 on the open road at speeds of 70-75. It also weighs 8900 lbs.!!! I had a utility body installed for my A/C business and it is a great deal heavier than the stock bed even when empty. It also has a headache rack that sticks up above the roofline so the drag is worse as well. Loaded up it's downright bricklike. I just installed the Firestone Ride Rite air bags on the rear to level the truck out. I'm happy with the mileage though. A gasser would be rediculous carrying that much weight.

 

Sorry but I dont believe you.....

 

I have to agree, I am on my second PSD, clocked 120,000 on the first one that I bought brand new and now have nearly 180,000 on my present one so I have put a few miles on them. There is no way that kind of mileage is possible at those speeds. Maybe the weight on flat ground and no wind, but the 4x4 makes even that hard to swallow.

 

OK! I'm not EVEN going to dispute anyone; I'm a new guy here. But I ordered my E-350 diesel just because I logged onto, read, and believed the hype that I heard first hand and from reading these forums. I'm a math major and have taught advanced math in local high schools for the past 20 years and WOULD LOVE TO BE ON HAND when anyone with 20 mpg computes their mileage. My E-350 got ~11 mpg solo and ~6 mpg towing before I installed the SuperChip (not much better now). That really pissed me off! After paying $42k for the vehicle, I found a rubber plug in a control box that accomodated the S/chip that I paid ~$400.00 for. Now I ask you; after paying $42k, why is there a rubber plug in the box? After that amount of money, why in the Hell didn't Ford put that chip in place? Go figure? Regardless, when I took the vehicle back to Ford and complained about the fuel economy, I was told not to believe all the HYPE that some people advertised, and if ANYONE got over 15mpg, well,... they don't get over 15mpg. This was told to me by the service manager at the dealership in Rockwall, Texas; call him. I renew my statement: I WOULD LOVE TO BE ON HAND WHEN SOMEONE CHECKS THEIR MILEAGE AND SAYS: WOW!! I GOT 20 MILES PER GALLON!! I've asked a couple of people that I know, and NO TAKERS!

Finally poorboy, be satisfied with the fuel economy that you're getting; it's not going to get much better. If you have a personal friend that claims higher, do a test with him/her. Fill it up, drive 25 miles and fill it up again. Teach them how to do math.

I'm venting now; I apologize. But with my 13 mpg, I really get tired........

 

To answer Paarothead's post (good post, btw); I have an e-350 econoline with Companion Capri Hi top package. For some reason, because it's a van, I don't have an inner cooler. Other than the IC, it's a standard 7.3 Turbodiesel DI, 3.55 rear end, and 4100A transmission. No mods except for a S/chip. Durability has been crap: Warranty replaced the water pump and passenger side rear axel bearings. Out of warranty, I PAID for the AC compressor clutch, TOTAL REAR END GEARS, torque converter, and speed sensor. To say the least, I've not been real happy with the mechanical performance of this vehicle; and I'm a Ford guy.

 

I've had my 2002 F250 PSD 4X4 C.C. Short Box 3.73 with cap for a little over a month. 315's for tires and Diablo chip came with it. 85,000 miles. I changed the fuel filter and put on the Fleet air filter. Filling it to the top so you can see fuel, I've been getting 14.5 around town. Just drove round trip 1,005 miles and got 17.25 on flat highways going 70mph keeping rpms about 2000. Thru the hills of Pennsylvania/western Maryland it dropped to 16.5mpg highway. Better than I expected. I imagine I could do better with smaller tires and am really debating going down to 285's. I have no idea what program the Diablo is either as nothing came with it. Towing my 5,000lb fishing rig I get 13. The onboard computer is always about 3mpg off of actual.

 

That's what my reaction was when checking it. I filled the tank to the filler neck to ensure that I was getting the correct "gallons used" to plug in to the equation. I am running Delvac 1 but I doubt it makes that much difference. There's another guy at work that gets very similar mileage.
I don't drive it like I stole it. I'm easy on the throttle. I want this engine and tranny to last.

 

Check your odometers accuracy. If it were not for the 70-75 mph part of your story I might go for it cuz I do a little better than that all of the time. Course I have 2 WD and am very stingy with the throttle. My odometer is within 1/2 of a percent mile after mile. Something has definitely cost me a couple of mpg in the last 2 or 3 months and I am still holding my breath for an idea from one of the experts here.

 

My odometer seems to be right on the mark. I run a GPS unit on long trips and it matches the trip odometer to within a mile or two.
I think a great deal has to do with driving style. Like you, I am very easy on the throttle. I also don't run the cruise control on trips because it tends to be too aggressive on hills. I probably run closer to 70 for most of my long trips. I don't like worrying about topping a hill only to find DPS on the other side. I have a CDL license and can't take defensive driving to reduce a ticket so I usually drive pretty conservatively. Besides that, I am a fireman and our dept. frowns on tickets that must be reported to supervisers. They've taken the fun out of driving!
In the city I am NEVER the first one off the line and get passed by many before getting up to the speed limit. I assure you that makes a huge difference.
I also run a blend of 50% biodiesel every 30k or so to clean injectors, etc. Stuff works great for that.

 

My 03 7.3 Crew Cab at best gets 10.7 pulling 10,000 lbs 5th wheel.....when not hauling we get an average of 13-14 mpg. Anyone wanna trade trucks?

 

I averaged 43 Smiles Per Gallon last time I checked.

 

Hey gjvoight. Your situation sounds like mine; ~ 13 mpg solo. But I'm only getting about 8 with my 10k TTlr and that's only if I keep it about 65. At 75, it drops to about 6. Does your truck have any mods that help you achieve >10 while towing? And no, I don't wanna trade; I love the fuel guzzleing beast, LOL.

 

Just did an interesting math problem involving my 11,768 mile journey this summer. Going through my very carefully collected credit card receipts I figured out the total of the entire trip including all city and highway as one figure and it came out to 20.1 mpg. Anyone else on this nifty forum ever kept that close of track for that many miles? That is one tough figure to argue with. This included carrying a very heavy load of hand and power tools including a heavy air compressor and every other tool a carpenter could possibly ever need.