So I recently got my 04 hemi ram with 105KM on it or about 65 Miles on it. It had a CEL for p0157 which is bank 2 sensor 2 02 sensor. I went on a trip up to my cottage and filled the truck up. Took 96 litres to fill at $1.14 a litre, so $110 and I got 470KM or 290 miles out of the tank cruising at 110 KM/H or 68MPH. So thats about 11MPG. My question is what can I do to improve this? From all I was reading the downstream O2 sensor doesnt affect fuel economy just tells if the cat is working, the upstream O2 sensor is what controls the fuel mixture. I have changed the O2 sensor since getting back and the CEL is gone but from the short highway drive I have took fuel economy seems to be the same. Thanks

 

Yep, rear O2 won't effect fuel economy UNLESS it ain't the O2 and it's actually a clogged cat. Shouldn't be the case with you though, as a new O2 would still be popping the CEL.

Best bet is the basics. Tune up, check air pressure in tires, 89 octane gas, clean the throttle body (a big one that most people don't do). Also winter blend gas is getting you. If you are running 20" wheels there is another MPG or two and if you have aggressive tires that can cost you another 2 mpg as well.
I lost a solid 2.5 MPG on my Grand Cherokee just by going from the soccer mom BFG tires that came on it to Nitto Terra Grapplers. Prolly would have lost another 1.5-2 more if I put mud tires on it...

 

well i got 20" mamba rims with 33x12.5x20 nitto mud grapplers!! I was using 91 octane pure gas though and tires properly inflated. How do i go about cleaning the throttle body?

 

https://dodgeforum.com/forum/3rd-gen...y-hemivec.html



33" Mud Grapps on 20s will be a mpg killer right there, plus with next to no sidewall to flex I'd imagine they'd suck ***** driving in winter up there.

Pure gas is still a winter blend (at least it is in the US). The pure means no Ethanol. Which is also a good thing. A 10% Ethanol blend costs you about 5% fuel economy on average...

 

I would say your mileage is about where everyone elses is. I get about that. As for cleanin the TB, just remove the intake hose that goes on the front, disconnect the electrical harness, remove the 4 bolts that hold it to the intake and get 2 cans of non-chlorinated brake cleaner and clean the back of the throttle body plate until it looks like new.

Other simple maintenance things like vacuum hoses, spark plugs, plug wires, air filter, tire pressure and big heavy tires and rims all take part in MPG

 

11 HIGHWAY IS WHERE EVERYONE ELSE IS????? I don't think so 'Weed. I've probably got the heaviest 1500 on this site and I'm getting 13.5 everyday driving and can just about nip 16 on the highway on my Fla/Ga trips...

 

Ok, so not every one per se but I think we can all agree the average is 12.5 +/-. I would say 11 is a tad on the low side but thats about what my truck would get.

 

Yea the mud grapplers suck for the snow!!! But i still thought on the highway I'd at least be able to get about 13-14 MPG at the very least. My 5.9 dakota used to get WAYYYYYYYY getter fuel mileage then this. Off 70 litres I would get 630 KM on the highway

 

Yeah, if your Mud Grapps were 33s on say a 17" wheel, you'd be able to air down some and get a bigger footprint in snow (picture regular shoes vs. those tennis racket looking snow shoes y'all are famous for in Canada, LOL). But with 33s on 20s there just ain't much sidewall for that. Of course the down side to airing down is a loss in fuel economy, but in the snow when it's safe handling vs. a crash, you can live with having to pump a little more gas in the old tank.

I still think old 'Weed is thinking OVER-ALL MPGs and not highway. Even with his big a$$ wheels and lift, I gotta believe he's seeing better than 11-12.5 strictly highway unless he's doing 80.

You've got another thing working against you also that I failed to mention, when it's sucking in cold air, your PCM is richening the mix. You'll see a little more power as a result, but worse fuel economy. A Hemi, with it's polysphyrical heads (yeah, the modern Hemi is a Hemi in name only) gulps more air than your old LA360 (5.9) did, so it'll be a little bit more susceptible to this factor, but not a lot.

I think you combine the Mud Grapps, 20" wheels, winter blend, cold temps, a possible dirty throttle body (I'd bet the back plate is gummed to sh*t) and a possible need for a tune up are keeping your MPGs low. Each one alone is no big deal, but in combination I could see a very real loss in fuel economy...

 

well im gonna pop the TB off and have a look. It seems to run perfectly though and it passed emmisions with flying colours so I doubt it needs a tune up but 16 new plugs couldnt hurt :P What plugs do these motors use? I'll go buy a whole wack of them tonight and throw them in