Our Itasca Sunstar 31KE (gas F53 chassis V10)is less than a year old and running fine. We tow a dolly with about a 3k lbs car on it. Last week I decided to really hone in on the mileage issues while on a one thousand mile trip south to FL and then back north to home. Over the course of the week long trip I went through four fuel stops. Road conditions were good all the way and the geography began in the piedmont of GA and ran down through the coastal plain of GA into central FL. About 1/2 the trip was interstate the rest was 4 lane limited access. Speeds started for the first 2 hours at 55 then were consistently 62- 63 thereafter. To limit downshifts I don't use cruise control on hills.My first tank I got right at 7.1 mpg running a varied 55 to 63 mph in the piedmont down through the coastal plain then onto I-75 south.The second and third tanks ran about 6.2 and 5.9 mpg mostly through Florida (flat and four lane- about 30% city driving). My speed on the hiway was set at 62-63 MPHThe last part trip was no city driving-some uphill into and across the piedmont headed north, all 4 lane 65 MPH posted highway, limited access back across gently rolling hills of GA. As I didn't have any time constraints I opted to poke along at 56- 58 all the way home to see what would happen to the mileage for the last 250 miles- averaging about 5 mph slower than the first part of the trip.When I got home I checked the mileage- and was pleasantly surprised to find my mileage had jumped to 8.9 mpg (from 5.9)!I knew it might be better but not that much.I am now contemplating holding at 56-57 on highways from here on out That's not a bad increase for an 80 gallon tank. Will continue to check.Sure I may have an extra hour of driving time on a long days run on the road but I can probably get used to it.Anyone had a similar experience on that general type of gas rig?

I think your mileage increase from 5.9 to 8.9 was due to the last gas fill not being completely full. Your ave would be 7.4 which is consistent with you other readings. I have noticed that all the time when refueling. Having said that I get better gas mileage at 55 than 65. What does your MH weigh? I have averaged 8.7 mpg over 80k miles driving between 55-62mph, 15k lbs 454 tbi. I think your mpg would improve by not using cruse control and keeping it in high gear by backing off the throttle when climbing a slight hill.

All of the analysis is futile. You cannot control the wind or terrain although you can control speed. In the end the cost difference will be negligible over the course of extended driving.Put the calculator down and enjoy your drive without worrying about MPG's.RV's are inefficient and use a lot of fuel your mileage will be bad. This applies to all types and brands. You can't fight the aerodynamics of moving a big box down the roadIf you want to conserve drive slower, even then your actual cash savings will be minimal.At some point you have to pay the fuel bill to play the RV game. Do it with a smile and enjoy the adventure.

"Fill ups” can vary quite a bit due to MH tilt at the station, gas nozzle shutoff adjustments, how quick you want to get done, wind, etc. Multiple fillings are the only true test of MPG. In the 52,000 miles I’ve driven my 31 foot 1998 Itasca over a 1999 Ford F53 V10 (with 105,000 miles on it) its averaged 8.14 MPG with a per tank high of over 12 MPG and low of under 5 MPG. As you, my normal speeds are 63 MPH on interstates and 56 MPH on other roads. The overall average MPG has dropped over past 52,000 miles from 8.44 to my current 8.14.Dave

We had a similar experience last year. Traveling across Nevada, my friend's first long trip with his truck camper. He decided to stick at 55 MPH and called back to me on the CB that he was 4 MPG better after a few hours. I was driving my 1/2 ton (loaded with gear), looked down at the MPG: 21. It really makes a difference.

As long as you use the actual gallons pumped, it doesn't matter whether or not you filled the tank completely. In spite of being as accurate as you can, the mileage really doesn't matter because it will vary from day to day because of weather, topography, traffic, and the type of fuel and the percentage of ethanol, which varies from tank to tank with a maximum of 10%, but could be as low as 1%. Basically it is best to just accept the fact that with ANY Class A RV, the mileage will be poor based on ANY standard of measurement.

Mileage surprise | Good Sam Community

Gjac
Explorer III
May 12, 2015
I think your mileage increase from 5.9 to 8.9 was due to the last gas fill not being completely full. Your ave would be 7.4 which is consistent with you other readings. I have noticed that all the time when refueling. Having said that I get better gas mileage at 55 than 65. What does your MH weigh? I have averaged 8.7 mpg over 80k miles driving between 55-62mph, 15k lbs 454 tbi. I think your mpg would improve by not using cruse control and keeping it in high gear by backing off the throttle when climbing a slight hill.
Lantley
Nomad
May 12, 2015
All of the analysis is futile. You cannot control the wind or terrain although you can control speed. In the end the cost difference will be negligible over the course of extended driving.
Put the calculator down and enjoy your drive without worrying about MPG's.
RV's are inefficient and use a lot of fuel your mileage will be bad. This applies to all types and brands. You can't fight the aerodynamics of moving a big box down the road
If you want to conserve drive slower, even then your actual cash savings will be minimal.
At some point you have to pay the fuel bill to play the RV game. Do it with a smile and enjoy the adventure.
dbates
Explorer
May 12, 2015
"Fill ups” can vary quite a bit due to MH tilt at the station, gas nozzle shutoff adjustments, how quick you want to get done, wind, etc. Multiple fillings are the only true test of MPG. In the 52,000 miles I’ve driven my 31 foot 1998 Itasca over a 1999 Ford F53 V10 (with 105,000 miles on it) its averaged 8.14 MPG with a per tank high of over 12 MPG and low of under 5 MPG. As you, my normal speeds are 63 MPH on interstates and 56 MPH on other roads. The overall average MPG has dropped over past 52,000 miles from 8.44 to my current 8.14.

Dave
Nik
Explorer
May 12, 2015
We had a similar experience last year. Traveling across Nevada, my friend's first long trip with his truck camper. He decided to stick at 55 MPH and called back to me on the CB that he was 4 MPG better after a few hours. I was driving my 1/2 ton (loaded with gear), looked down at the MPG: 21.

It really makes a difference.
rgatijnet1
Explorer III
May 12, 2015
As long as you use the actual gallons pumped, it doesn't matter whether or not you filled the tank completely.
In spite of being as accurate as you can, the mileage really doesn't matter because it will vary from day to day because of weather, topography, traffic, and the type of fuel and the percentage of ethanol, which varies from tank to tank with a maximum of 10%, but could be as low as 1%. Basically it is best to just accept the fact that with ANY Class A RV, the mileage will be poor based on ANY standard of measurement.
ferndaleflyer
Explorer III
May 12, 2015
I have drove mine over 100,000mi and not once have I ever checked the fuel mileage. If I want to go I have to put fuel in it regardless of how much it will use.
CG_Dawson
Explorer
May 12, 2015
Right around 7 is our average for 55,000 miles.
mike_brez
Explorer
May 12, 2015
Mines a DP I usually really don't check mpg but sence the rig is fairly new to me I just had to know. After purchase a1500 mile trip from Florida to Ct. with no toad cruise set at 63 almost 10 mpg. From Ct. to Nashville Tn. Pulling a Jeep Wrangler just over 9mpg. From Memphis Tn. to Berlin Ohio I needed to do this in one day. 14 hour drive some slow traffic around Cincinnati we were pushing it at between 70-75 mph pulling the same wrangler just over 7.5 mpg.
Dale_Traveling
Explorer II
May 12, 2015
Individual fill up mileage calculation is never going to be 100% accurate. The problem you'll have with the math is the assumption that the fuel added during a fill up was an exact replacement for the amount burned. So in other words you'll need to fill the tank to the same level each time. What makes this even harder is the volume of fuel the average class A can hold can increase a large deviation in the numbers. Really easy to be off each time by several gallons which will shift the numbers. Environmental factors (wind, terrain, traffic and such) will also cause deviations with each fill up.

I do track mileage with each tank but I'm watching for a large change downward which might indicate a chassis or power train problem that needs attention. Beyond that anything else might be akin to a quest for the Holy Grail which for me would be 9 MPG over several fill ups, in a row.
hershey
Explorer
May 12, 2015
Every vehicle, including MH's and haulers have a sweet spot. My MH's is about 62 mph. Finding my sweet spot is from thousands of miles of driving and also the help of the Silverleaf engine monitoring program. Different terrain and wind conditions also call for a change in speed to get the optimum possible.

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