So, I just picked up a really nice Magnum - 2007, 45k miles, and I love it! It runs just beautifully and the power is amazing. My main concern is the relatively poor mileage I'm getting. I've never had a car that I couldn't get EPA highway rated MPG out of - if not better than EPA. The Magnum R/T is EPA rated for 22mpg highway, and the best I've gotten is 19mpg. This was on a test run on a flat, straight road with no stops and using every hypermileing trick I know. On average highway trips I'm only getting 17mpg. I realize that this is a big hemi engine, but 25% below EPA seems pretty bad. I know that MDS is working - there's a very distinct change in exhaust note when MDS kicks in.

One thing I'm not sure of is the transmission. Does this transmission use a lock-up torque converter, and if so, how do I make sure it's working? I'm used to 4-speed automatics with lockup - the lockup is quite apparent, it's almost like another gear. Lockup will usually drop engine speed by a couple-hundred rpms. I haven't seen that happen in this car. Otherwise the transmission seems to operate normally for a five-speed. At 60mpg the engine is turning at almost exactly 2000rpms.

Anyway - does anyone have any suggestions for things I can check? Or is this simply the way this car is, and I just have to be content with 17mpg?

Thanks for any help.

Scott

 

17 mpg isn't unheard of, and yet, I heard them getting 25 mpg hwy. remember, the EPA ratings are averages.

The only thing you can really check if the car is running good is for tune up stuff. You said you bought it used. What kind of oil, gas, filters are on the car? From factory, the car is tuned for 89 octane or better. Are there paper filters and how old are they. Regular or synthetic oil? Dodges computer will look at all of these and make adjustments accordingly. Last thing is tires. If the car is running good, all of these are where I would start, especially if I bought used. Oh, and don't forget, you bought a V8, so you may be able to pick up a mile or two better mpg's, but your lead foot will determine that as well... LOL!!!

If you do anything to the car, give it 50 miles of driving for the computer to learn, then perform your tests.

 

I picked up a 2007 a few months back myself, it's a great car and a huge upgrade over my old 4Runner as far as power, mpg, and road manners (then again it doesn't have mud tires). That being said the best I've seen was just shy of 20mpg. My mpg numbers are a little iffy though, my speedo is off by 5mph at 60 so on second thought I haven't a clue what my mpg is looking like. I know in town my mileage suffers drastically, but that's mostly due to stop and go traffic and a temper fueled lead foot. In retrospect my post didn't really contribute anything here.

 

I get 19 - 22 MPG in my 2006 5.7 2WD. I drive 50/50 2 lane roads vs. HWY. If I'm on the highway, I get 22MPG most every tank.

 

Apparently it's just us Bighorton.

 

I just bought a 2005 RT AWD and read that tire preasure can be a MPG changer, on checking mine all were @ 28 psi, they suggest 30 so I went to 31psi and hiway mpg went from 19.7 to 21.9. Now on the next oil change I'll put in Mobil 1.

 

You mentioned 2000rpm at 60. That seems a bit high. I don't hit 2000 until around 70. May be trans or little teeny tires.

 

I have a 2007 SE with the 2.7 and I'm also at 60mph/2000 rpms's. 75 mph at 2500 rpm's. Seems like the tranny should be kicking down sooner. So are these numbers where they should be?

 

Every vehicle since about 1985 uses a lockup TC. Are your tires stock size, does it need a tune up (plugs, etc)? What is your rear ratio? Stock should be 2.65/2.82. If someone changed that it will affect it. Before I switched my 06 R/T to a 3.06 rear I could get 27mpg on a flat surface, cruise control set to 60. Something is off.

 

In my '05 RT I use dino oil and run regular fuel (87 Oct). My tires are oversized on stock rims - 245/60R18 and I run them at 35 psi. On the freeway at 70 mph I'll average between 22-25 mpg. I also use my cruise as I find that if I foot throttle I'll only average 18-19 mpg. So things like using cruise control and keeping an eye on tire pressure are important. Also remember that these wagons weigh in at 4000 lbs so how much other stuff you carry will effect mileage.