My 2004 Dale Jr is only averaging around 23-24 mpg on mostly highway driving. This seems low considering that the window sticker says I should be getting a high of 28mpg. I also seem to remember some of you stating in the past of getting around that high.

This is what I have done to this car in the 6,000 miles that I have put on it since buying it. New AC-Delco plugs, Delphi wires, Delco air filter, fuel filter, pre-cat O2 sensor, MAP sensor, and pcv valve.

The intake gaskets were replaced with the new aluminum ones. new valve cover gaskets. New delco thermostat and coolant flushed and replaced with high mileage green stuff. Tranny fluid and filter changed with Dextron VI. New tires and rims. Four wheel alignment. Engine oil and filter changed twice. Borla cat-back exhaust system.

Car has good power and runs fine. Never any CEL's. The best mileage I have gotten was on a trip from MO to TX last year on vacation which I averaged 26mpg

I don't use the overhead display to determine mpg's which always reads about 3 or 4 mpg higher than what I actually get. I figure mine by hand.

Am I expecting too much on getting better mileage? Do I have some issue that might keep me from getting better mileage.?

Let me hear what you supercharged guys and gals are getting on mileage figured by hand. Thanks.

Wayne

 

If I cruise at 60-65mph I get an average around 33mpg unless there are a crap load of hills everywhere. If there are a ton of hills then I only get around 30ish mpg. Last Thursday I made about a 240 mile trip & I averaged like 32.7 going from 60mph to 70mph going there. On the way back I only averaged like 26 bcuz for a big chunk of the trip I was going between 70-85 mph bcuz I was running late

The supercharged montes are only suppose to get about 28mpg on the hwy I think. Idk why mine is so good but I'm not complaining. When I get in the city though my mpg drops to 20 if I'm lucky.

 

I do no highway driving. My trip to work is around 40mph on the average with not too many traffic lights and I'm averaging around 22mpg.

 

Crappy 22, for me.

 

On my 3000 km trip to, from and around Charlotte I averaged 10 L/100kms (according to the fuel computer). That translates to 23.5 US MPG (or just over 28 Imp MPG) - the same as Wayne. I kept to speed reasonably close to the speed limit, but there were certainly some mountains on the way.

How in the hell are you extracting that from yours Britney? You should be driving in Nascar if you can get 40% more milage - very impressive. That's how races are won...

 

Well, then maybe my mileage is normal and the window sticker was highly optimistic. What sucks is that my fiancee's 2007 Mustang GT with the 4.6L V8 gets the same mileage as mine or a little better.

Wayne

 

If mechanically you should be getting the mileage, but you just aren't.

Then you have to go to the PCM, though that might not be a very realistic approach for you. The tune is probably just off, dumping too much fuel.

 

I'm averaging around 25 - 27 mpg. on highway

 

I have noo idea how I'm getting that. My car is soo weird! I baby the heck outta it though so idk if that has anything to do with it or what. I've also been only using BP in my monte bcuz the premium is cheaper there than anywhere else in wentzville sooo maybe their fuel really does help get better mpgs lol haha i wish i was a nascar driver. that'd be soo tight! But remember my post a few months ago how my monte was getting only like 25mpg on the highway, once the warmer weather set in & kept getting over 80 degrees, my mileage jumped so yeahhh I'm as confused & shocked as you guys are but like I said before, I'm most def not complaining lol

 

Back when I had my gtp- I was doing about 27-30 on the highway depending on what speed I'd run (all highway though).