Ok well I figured I'd start a thread on mpg's. I have been having horrible mpg's on my 04 f350 6.0 so I'm trying to figure out how I can do better than 10.3 hand calculated ( filled all the way to the neck). I just drove 348 miles on a tank and 86 miles of that was highway. I drove normall this time around not like I stole it... Just filled it up had 1/8th of a tank left, took 33.75 gallons. Now I was only getting around 8.5-9 mpg's but I changed my tire size on AE. And this is all driving empty. Has 3.73 LS gears with 305/70/16's

So I need some help on what to do.
I cleaned turbo( slight increase in boost)
Updated feed and drain for turbo
Cleaned ebp sensor today( it was clogged)
Oil is only 1,000 miles old with filter
Both fuel filters are 1,000 miles old
Clean air filter
Checked all intercooler boots
No cel or codes ( I noticed there is alot of oil in the boots and pipe on drivers side?)
I also run a certain boost when I fuel up ( grey bottle I think it's diesel service?)
This truck is driving me nuts!!! Sold my new ram to get better mpgs when towing my sleds!!

Any idea on what to change check or do would be gladely appreciated!!!

 

Do you have the most recent FICM flash from the dealer? If you do its not helping mileage, also how heavy is the flat bed you have? What size tires are you running? Are you talking city mileage or highway? I know for a fact my 250 gets around 13mpg in town, 18ish mpg on the highway below 70mph on 33" tires and 20" wheels, that is custom tuned.

 

You say you went 348 mi 86 was highway, what was your speed on the highway? What was the other 262mi? around town? Was it all one trip or over a period of days? Did it idle in the mornings to warm it up? I find its best to check for a trip, like fill up go 86 highway sto and top it off then figure it. You have to spend some time filling it to get it full, when its in the neck push on the side of the truck and shake it side to side to see if it "burps". Your in PA so its probably blended fuel still as well. Your tires are a little taller than the originals so that should help you. Do you know what strategy you have? Some later ones knocked milage by like 3-5 mpg. PHP does "rollbacks" to older strategies, look at their website. I have a 2003 with an old strategy and 3.73 gears and 285-75-16 tires, I run an SCT with Erics Extreme Race tune and get 15-16 running around and have gotten 20-21 on the highway. I lose mpg if I go much over 65mph.

 

The 348 miles took me 2 weeks, all city driving and 5 min warm ups and 86 miles of the 348 was highway cruise control set at 70 mph. ECM= VXAP2N2.HEX I have been talking to bill at php about upgrading my edge evo to a gryphon with the FICM tunes ECM and TCM rollback.

 

I would say maybe not the best for checking milage. fill your tank shaky-shaky and all that get it up in the neck, takes some time. get on the highway and set it at 65 and go for a good ride like 100mis, then top it off the same way and figure your mpg. It should be close.

I dont know much about the gryphon yet, but I think you are on the right track with the rollback. It should be interesting to see what improvements you get.

 

Don't forget we're on winter blend now and it usually knocks 2-3mpg off....

I get between 13-15 on 35's with 3.73's and mostly county highways. Lots of romping though.

Is your EGR deleted? Tuning? A rollback from PHP is probably a good idea.

 

Egr is deleted, everything is in my sig. But it has been 60* here in Erie and I have noticed that it is doing that 2 stroke thing like I mentioned a week ago.( after warmed up shut it off for a second then take off again and it will start fine but heller you get on it half throttle is runs like a 2 stroke too rich with white smoke.) and I drove arond yesterday and it does it all the time now? Get on it and it won't go... But if you ease into it its fine... Fuel pressure is good. So I'm wondering if my injectors are going out?

 

I would be more concerned with the FICM, not the injectors.

 

Ficm test good all three positions never go below 47... That's why I sent you a message about mine being bad but reading good.. On AE if I watch it it fluctuates between 48-47.5-47, and the idle fluctuates with it

 

I have a spare I'm putting together this week, when I make sure it's good, I can send you a known good one down your way to try out if you want, just cover the shipping on it ~$12 or so. If nothing else, it would at least eliminate it as a possibility...

You said your batteries are good too right?

Also when you did your tire size with AE, did you verify your speed with a GPS? The tire sizes are not 100% accurate with AE. I think I had to do like a 33.5" tire in AE to match up to my true 35" tire. I would verify this just to be sure. Your mileage is horrendous, there is something not right here for sure.