I've been uncharacteristically low on MPGs this fall/winter. (It HAS been much colder, but I was seeing the decreases before the real cold set in.)

2010 Crew SLT, 5.7, 4x2, 3.55 gears, 58k miles.

I'm 70/30 highway/city and normally average 18ish combined in the spring & summer and 16ish in the colder temps. I think that's pretty decent.

This fall I started seeing my mileage drop; got new tires and it seems like it just keeps going down. 15 mpg to 14... I'm now around 12.5-13 combined driving. I just changed all my plugs ~500 miles ago and they really didn't look that bad but I figured I was closing in on 60k and thought maybe I had a bad one but that didn't change anything. Changed the oil 1500 miles ago, can't really think of anything else obvious. Fuel filter maybe??

I know winter blend gas gives worse mileage but this seems uncharacteristically low. This is my 3rd winter and it's noticeably worse.

Any thoughts or suggestions?

 

Great data Dusty. Very thorough. I expected as much concerning the computer. I imagined they were more accurate then people wanted to admit. As my accountant always says "Numbers never lie, only people lie!"

 

Something just doesn't sound right. Forgot where you are but if in the REAL cold north lots of factors drop the MPG other than winter fuel I.E oil viscosity, not only engine when its cold but also tranny, rear- end, wheel bearings etc. While not as noticeable as say 20 yrs ago, cold still has an impact.
I have basically the same truck, yr, engine, gears with 20" wheels as i suspect you do. My driving is more like 70% town, 30% highway. I average around 15-16 overall. Highway if I keep it say around 70 i can expect 18-20 now in the winter and at that speed in the summer I can expect 20-21 all day long. However a more likely scenario is around 80+ on the highway averaging 17-18 winter, 18-19.5 summer. The only time it drops much is towing the boat and then I do not even look at it!!! All scenarios its 2-5 mpg better than the 2 Ford 5.4 and LOTS more power both towing and not.

 

You could have a slow, lazy, or otherwise defective sensor somewhere in the fuel delivery and monitoring system, but I've not heard of one on any Hemi since the 2007s.

In all probability your drop in gas mileage is due to (1) the drop in ambient temperatures and/or (2), a change in your driving style.

I've developed a driving loop that I use as my 'standard,' if you will, which is a specific road and distance that I drive to appraise engine fuel economy (Yes, I'm that ****!). By that I've determined that I'm a full 1 mpg less than my summer time drive.

That aside, my last two tanks were in the 13s, but almost all of my driving was short trip (under 5 miles), and consisted of a lot more engine idling than normal. And the roads have been snow covered better than 50% of the time, which adds to rolling resistance. Plus I've been in a hurry a number of times, which means a little more throttle than necessary. These factors can really hurt gas mileage

For piece of mind you could have your Dodge tech. check the fuel system sensors with their diagnostic tool to see if they are operating within the correct range. At 58,000 miles those components should still be under warranty.

Bests,
Dusty
2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 99,000 miles.

 

This is also probably the worst winter any of us has seen in a long time and the cold dense air will kill your gas mileage

 

I have an 09 ram 1500 4x4 3.55 and 20" wheels as well. My mileage is usually an average of 13-14. Sub zero temps was 11-12 if I was lucky. During the spring-fall the best overall I have seen is mid 16mpg. I changed my driving style with all different tunes with my flaspaq tuner. Mileage xs just sucks. It detunes the engine, mileage is worse than stock in my opinion. Even in nice weather. 91 performance tune does the best. Although doing 75 on the way home Today with 93 performance tune it showed almost 17.7 on my evic. I was doing 70 at 15.6mpg for 10 miles steady. Almost makes me want 4.10 gears. I tow a camper and I didn't buy the truck for mileage anyhow. But after reading the posts above I may switch everything to royal purple. But not until it's warm again. My truck has Goodyear duratrec 285/60/20 and I been doing 70 mph when **** ant cars are not in my way on the interstate during the nasty snow storms we have had in illinois for the past couple months. To me that's why i bought a 4x4. To tow my camper wherever I may roam. And to kick some butt in the bad weather. If I was concerned about mileage i would drive my wife's honda.

 

I'm going to guess that you do more stop-and-go, around town driving than steady highway. Your experience is typical with the 3.55 gear set, especially with the 20 inch tires. Most of the people I talk to are actually doing better with the 3.92 gears, and that's because like the majority of folks they are doing more around town driving than they are expressway or highway driving. The 3.92 or 4.10 gears probably would limit your highway mileage, especially above 55 MPH.

Bests,
Dusty

2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 99,000 miles.

 

I'm pretty gentle on the gas (tightass trying to squeeze every last dime out of my tank) so my driving style really doesn't change much.

I'll give it until the warmer months and go from there. I have to take it for that recall soon so I'll see if they'll check the fuel system sensors while it's in. They probably hate people like me though, I'm a DIY maintenance kind of guy so they don't get the luxury of bending me over the barrel for routine maint.

Thanks for the tips guys. I REALLY hope it's just the winter.

 

Steve, we had four days of high 30s to mid-40s and I saw gas mileage jump to 17.3.

Regards,
Dusty
2010 Ram Big Horn 1500 Quad Cab 2WD, 5.7 Hemi, 545RFE, 3.92 LSD, factory dual exhaust, 20” wheels. Now at: 99,000 miles.

 

I get 9.9-10.3mpg in my ole truck.


Just curious, but is all 4th gen front bumpers the same? Saw some 2nd gens with them on and might consider one.