Better mileage

[max2fat]

Have a 1994 Itasca 27 foot MH with a 454 cid- just did added new plugs and wires - runs better but need some input from our senior members - I am a newbie Thx Max

[Skip426]

Welcome to iRV2.

Fuel mileage , is mostly about your right foot , 20% variance in mileage between drivers with similar RVs depending on driving habits .
Keep the speed down , choose routes where you can maintain speed , and avoid full throttle operation.

[max2fat]

Hey Skip426 - thx - time to start educating my foot Thx Max

[Soppy]

Has anything been done to the motor (air intake , headers) ? You could check the ECM for stored codes . Check the timing (be sure to disconnect the timing wire). Replace the oxygen sensor.
I have the banks system ( cold air intake & headers) and was only getting 5 mpg. I replaced the oxygen sensor with a 4 wire heated one . With the headers, the original 1 wire oxygen sensor would not maintain operating temperature and the ECM would keep going into open loop causing poor mileage . I found the timing at 2 degrees , so I set it to 6 degrees. My mileage went to 7 mpg. I am travelling just under 60 mph . Most of my trips are less than 100 miles so it takes a long time to see if the changes I make affect the mileage.