Hey everyone, I'm not sure why but my truck has been declining in its gas mileage. It's an 02 Ram 1500 with the 4.7 V8. It also has the short bed with RWD. I do drive lots of city and not so much highway, but I should be getting around 14 City. I do have a superchips tune on it (87 Octane), but for a few weeks I did have the Tow Tune on (to see the power difference). In April my coolant reservoir started to leak, so that was replaced very quickly. The truck drives and runs great. Shifts very smooth and drives like a dream. I attached pictures of the gas mileage and all the sensors and things of that nature.

Sensors all passed...


RPMs and Voltage Look Good...

Fuel Trim hasn't gone past +/-10%

Gas mileage dropping...

 

Everything looks good there. Things are working as they should, according to the computer. Do you get gas at the same place each time?

 

You know, as a matter of fact I do. I go to the same place every time because their gas is the cheapest near my house. Should I try a different gas station next time? I also forgot to mention I'm currently running a can of seafoam through my gas right now, and I still have another can.

 

Don't know if the seafoam will make any real difference. I suspect the major changes you are seeing is just what blend of gas they have for the season. My gas mileage drops a couple points in winter as well.

 

Here's a pic of how many miles i've driven since a full tank (my last fill up). If my math serves me correctly I've been averaging around 10 MPG with a 26 Gallon Tank, which scares me... and yes, my Tachometer is not accurate below 2000 RPMs, so that doesn't concern me.

 

It's the weather. Well, the EPA response to the weather. You can blame Congress and the EPA for mandating Ethanol use in gasoline. When they adjust the fuel blend, I've seen major changes in economy. I'll bet your actual Ethanol blend was around E5 and is now around E10, possibly as high as E15. I know Countrymark premium fuel is pure gasoline. I believe you can get Ethanol free gasoline at some Sonoco stations too.

 

Ya I might try to stop by a more "premium" gas station if you know what I mean. Is Sunoco the only gas station that is Ethanol free?

 

Around here, I know Country Mark and Sonoco stations can sell Ethanol free. Country Mark premium has no alcohol and Sonoco has Ethanol free pumps. When I go visit the kid and her family in Gulfport MS, I see stations advertising "Ethanol Free". I suspect this may be for marine use. Here's a link to find ethanol free stations.

https://www.pure-gas.org/

 

Well I checked out what was nearby me, and it was all 94 octane or above that was ethanol free... I live in Massachusetts but I am right next to the border that crosses into New Hampshire. I might run up to New Hampshire if I decide to throw a 91 Octane Tune on my truck...

 

It's mostly just premium around here. Marine and Aviation gas are generally higher octane but aren't really designed for automotive use. Racing fuel can be used in a car or truck but it's so expensive you're better off just using regular gasoline. Aviation gas can burn holes in pistons since it's designed for steady running not speeding up and down as well as the tax evasion risk you run since there are no road taxes paid on it.