cancel
Showing results forย 
Search instead forย 
Did you mean:ย 

MPG getting worse on Motorhome

Public_Guardian
Explorer
Explorer
Hi-I have a 1997 22'Shasta Ford E-350 chassis with V-10 triton engine. Class C with over 100,000 miles.

The rig was pretty consistently getting 10MPG. About a year or more ago the MPG dropped to about 8.5 MPG. When I changed the fuel filter the MPG went back up to 10MPG again. Over time the MPG dropped again so I put in injector cleaner and again the MPG went back to 10. Lately, changing the fuel filter does not make much of a difference to MPG. Putting the injector cleaner in still raises it back to 10MPG but the MPG drops down once the injector cleaner is out.I put in a new air filter during this time and had the spark plugs changed out. Neither seems to have had any effect on the MPG situation. Anybody have an idea of the cause consistent with the above facts. I assume it is in the tank-lines-injectors somewhere. All help is appreciated. Dennis
16 REPLIES 16

Golden_HVAC
Explorer
Explorer
Hi,

I got a check engine light when my oxygen sensor went out. Changing it improved the mileage, so did changing to 91 octane gas. Fuel injected systems have anti-knock sensors, and low quality fuel will cause the computer to make the fuel mixture rich and/or retard the timing, both will lower the fuel mileage. Perhaps the fuel injector cleaner fools the system to thinking it was higher octane fuel?

Anyway I figure the 91 octane fuel will cost about 5 percent more, but save my by using 10% less gas.

Good luck!

Fred.

PS: THe oxygen sensor is only about $50 and can be installed in your driveway. I used one made for the 96 F-350 with 460" engine, same as my 97 motorhome has. It fits fine, actually there are many vehicles that use that same oxygen sensor. The biggest difference between O2 sensors is the length of the wires and shape of the plug on the end.

Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a

Porsche or Country Coach!



If there's a WILL, I want to be in it!



I havn't been everywhere, but it's on my list.

Kangen.com Alkaline water

Escapees.com

B_O__Plenty
Explorer II
Explorer II
Fuel filter has nothing to do with mileage. All it does is filter the dirt out. Injector cleaner might help..There are many things that can cause a decrease in mileage. Quality of the fuel, wind, speed, load, engine wear, tire pressures. The difference you see is probably normal. You will never get the exact same mileage with every tank of fuel. When it drops to a consistent 6-7 mpg then you might have cause for alarm. Just drive it..

B.O.
Former Ram/Cummins owner
2015 Silverado 3500 D/A DRW
Yup I'm a fanboy!
2016 Cedar Creek 36CKTS