Why does my gas mileage suck?

Professor

New member
Okay, I didn't buy the Merc to be a Prius. Gas prices are coming down and that is nice. However, it seems like other Marauder owners (even with 4.10 gears) get much better gas mileage than mine. If I drive it like a hypermiler (nice easy starts, minimal braking, keeping the rpms down) I get 16 mpg. If I drive it like I stole it (not often) it will drop to 12 mpg. But generally, driving it daily amounts to a consistent 13.5 to 14.5 mpg. I have friends who get 19-21 around town and 28 on the hwy. The only way I could come close to doing that is if I gutted the interior, removed the trunk and bumpers and ... well you get the point.

So ... why is mine so thirsty? It drinks gas like a suburban. Obviously, not something easy to diagnose ... but where would you recommend starting?
 
Brakes are new. Alignment is new. Tire pressures are normal (38 up front, 36 in back .... yes I know those are high).
 
How are you calculating gas mileage?..fill the tank, set tripmeter, drive your week, fill up again and divide gallons needed to fill it up into the mileage on tripmeter?
 
I don't believe the folks claiming 22-24mpg or 350 miles to a tank.
I drive my beater easily and get 300 to a full tank on a good week.
I get 200 to a tank in cold months with winter blend gas
 
I don't believe the folks claiming 22-24mpg or 350 miles to a tank.
I drive my beater easily and get 300 to a full tank on a good week.
I get 200 to a tank in cold months with winter blend gas

I get about 250-280 with my trilogy on the winter blend and have gotten 345 to a tank on a trip at like 70-75, but I have 3.55 gears.

My old N/A marauder with 4.10s got 250-280 with everyday driving and like 320 on a trip.
 
Mine has a tune, I average around 14.5 around town.. They're rated at 17 city.. I noticed today after the first tank of winter blend, I got 13.0... Lovely.. I'd be open for suggestions also. Mine's stock minus mufflers and a tune. Plugs are new, fuel filter is new.
 
I have never gotten 28 mpg on the highway in my MM. I get about 220 or so miles to a tank of just city driving and I have a lead foot. On the highway I get about 19-22 mpg depending on my throttle foot. Thats with add ons and a Mo Tune.
 
MILEAGE app:

From 9/23/2011 to 12/01/2014

Avg. fuel economy: 15.84 mpg
Worst fuel economy: 11.15 mpg
Best fuel economy: 23.65 mpg
Avg. distance: 228.14 miles
Min. distance: 89.00 miles
Max. distance: 403.00 miles
Est. cost per year: $869.29
Avg. cost per mile: $0.23
 
I have friends who get 19-21 around town and 28 on the hwy.
With Marauders? I don't believe that number for the highway. I can get 27 with my DD, but that's with 2.73 gears. The Blackbird got 21 on the way home from Lidio's so I can believe 23-24 with stock gears, but 28 sounds like a fluke.

Lazy O2 sensors can cause poor economy, as can the other things mentioned: tire pressures, alignment, dragging brakes, and especially driving style.

Please don't take offence as I don't know you, but I have lots of friends who would be considered "good" drivers in that they are generally courteous, but they are definitely not good in terms of fuel economy...they don't maintain an even speed and rush up to stop signs then jamb on the brakes. They also follow too closely, needing to constantly brake to keep from hitting people. All of this can drop the gas mileage like a stone.
 
The best that I have ever done was 24.5 MPG to and from Louisville, KY in 2008. That trip was right at 1,200 miles round trip plus about 250 miles of local travel. I would categorize the trip as a "relaxed" run between 75-80 MPH about half of which was in convoy with other MMs. Don't think I have ever matched that running alone.
 
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