I have a bone stock 2005 F350 DRW FX4 6.0 Diesel. I've been averaging 10.5 to 14 MPG city. Haven't really done any hiway driving yet. Does anyone have real world suggestions to improve mileage? I live in Colorado, so deleting all the EGR stuff is pretty much out of the question and Colorado requires yearly emissions testing. Thanks.

 

Drive slowly. Don't accelerate quickly. Make sure air filter is clean. Maybe get FICM and PCM tunes

 

Are those numbers hand calculated or the trip computer numbers? Also are the tires stock size and what gear ratio are you running? Are your 4X4 hubs locked in manual or in auto?

 

Don't underestimate the benefit of tuning. Your mileage numbers are truly horrible. Have you checked the health of your FICM? It could be that it is weak and you don't know it.

17. Can I test my FICM to ensure that it is the culprit?

 

I've got a 2006 DRW stock 6.0 and that's about what I get for City mileage too. Highway tops out a little over 16 and I'm a fairly conservative driver. Don't know all that much about rear end gearing, but I'm guessing those low numbers have a lot to do with the 4.11 rear end on the DRW.

Towing my 22' boat I'll get around 12 mpg average on the highway. Boat and 5,000+# worth of camper and its usually around 10.5.

 

It's a really good point about the rear end gearing. That is huge and something I overlooked. So...do we know what the rear end gearing is?

 

gone from 15 to 17 with Atlas 40 and a street tune - and got so much more power as well it's exciting in the dry as well as the wet...

 

I'll have to look up my rear gearing. Tires are Michelin low resistance at 70 psi. They go to 80psi Max. Thanks for the FICM suggestion, Im waiting for the ol lady to ok the scangauge II. Before you guys laugh, wife is a banker. She is the number 2 banker in the states and I have zero debt. Lol

 

I was pretty much without debts until the divorce...

 

If the wife is a banker Doc, you should talk with her about the Edge Insight CTS2. It is SUCH a much better monitor than the SG II. The upshot there being that as it audibly alarms when bad stuff happens it will actually catch stuff hopefully early enough to prevent the truly bad from happening.

Euroman - glad to hear that you are liking the tune and the FICM, but sorry to hear about the divorce. I've yet to hear of anyone in a better financial place following one of those...

 

Been looking at the Edge CTS2. Seems to have more info and a nice screen that is programmable as well. Upgrades I'm looking at are a blue spring, 4" exhaust, BPD EGR cooler, coolant filter, and BPD oil cooler down the line. Maybe some extra lights. Not into hopping it up, but do want better mileage and longevity. My 71 Bronco has flipped the odometer so many times I don't know the mileage any longer. Would like to see this truck last as long.

 

Running cold will ruin mileage. Dash temp gage is an idiot gage. Only goes out of range with extreme temps.

Running below 175-180 (i don't remember the exact number) causes the truck to throw more fuel in because it thinks it hasn't warmed up yet.

 

I'm about the same for mileage. We are heavy and the 4.10 keeps mileage low. I run with a 90 gallon in bed tank so out of 128 gallons of fuel with mix of towing and town driving I average 11.7 or so.
Good luck on your quest. I accepted it as nature of the beast and am fine with it.

 

I totally understand. When you're ready to move forward, give us a shout. We carry everything on your list and, well, pretty well everything else!

 

I've seen some nice gains with a combination of things. Atlas 40, cetane booster and a 200* Mishimoto tstat.
I use Ford cetane booster or Optilube, both great choices.
Not uncommon to see lower 21, even 22 mpg hwy and around 16 city running tires slightly larger than stock.
I would also say switch to 5W40 syn oil if you have not already.

As far as your wife approving the SGII, I would tell her it's going to save you money in the long run and not worth waiting for.