eliteamg

Hey guys, can anyone help with suggestions why my e55 is only getting 9 miles per gallon? I used to get 15 mpg local driving but now 9. This is getting ridiculous

shardul

iTrader: (1)

please post the mileage on the car. You may want to check your 02 sensors.

eliteamg

I currently have 67k miles

shardul

iTrader: (1)

ok start off by
1. replacing air filter
2. check all 4 o2 sensors to see if they are sampling at an acceptable rate.
3. replace all spark plugs (even though plugs are good for 70k to 80k miles on a stock car)
4. connect the car the a obb2 scanner and see what the long term fuel trims are

BTW I forogt to ask about your driving style, if you are driving aggressively your 9 mpg may be acceptable.

Cylinder Head

iTrader: (1)

Should he check his cats as well?

eliteamg

About a month ago I cleaned my K&N filters and this week doing a resenator delete on my exhaust so I may take out the secondary 02 sensors.
Spark plugs were replaced at 50k miles tuneup.

Most of the time I am driving local and do not drive aggressively. I will have my mechanic look at it next week.

Thanks for your advise.

CLKCLK

Geezzz, I thought mine was the only 55 taking gas shower lol. I still get 13-15 mpg local driving

zneB-sedecreM

7.8 MPG in my CL55

PACougar

I often only get 9 MPG, but I think it's self inflicted

chawkins2001

I saw 23mpg on the highway last week.

aghakauve

Ill see 9.5 every now and then. But I often see 11-14 city and 20-23 on the highway.

SFBIGBODY415

12 in city 20-23mpg on freeway

nizzle

I often see 8 - 10 mpg but only when "self inflected" as someone else mentioned earlier. However, "normal" driving around town = 11 - 14 OR highway = 18 - 21. Combining everything for the last 1,100 miles I've been averaging 13.4

WPOZZZ

Do you smell gas around your car? If so, it could be leaky fuel pumps.

desired_speeds

I average 9-13 mpg usually. Strictly weekend "fun" car.

newlyAMG

Yeah no more than I know about 55s, I'd say it could be the fuel thing? Assume anything that would cut your mileage 25-40% would throw a CEL for something, bad sensors, clogged cats, something. Canged the oil recently? I'm sure synthetics are much better, but I used to notice mileage increases after oil changes in my cars that took conventional.

Toadster

clogged fuel filter?

TheVazha

~9 MPG city and I can get up to 17-18 MPG hwy. Had plugs replaced at 5000K miles ago and have K n N filters. If I'm at highway cruising and do a "Trip Reset" I can get over 22 MPG.

I would guess it has to do with your driving style and traffic as well. When at the dealer I get her back and the dash reads ~4 MPG (from idling for an hour). I mean, this is a 7 year old ~500hp 5.4L motor, what do you expect?

kompressede

23 MPG on E85?
If that's what your getting with the "corn"? that is amazing

BBBSS

Toadster

danlnyc

I thought 9 mpg was normal???? I get like 9-10 mpg local, and 16-20 highway.

03'55AMG

I get 8-9 city and about 15 highway, City is poor because I always drive in manual just to hear the motor music up to about 4500 RPMs, but never really more than 1/4 throttle. I also love hanging in 2nd gear around 3 grand and just having the throttle far enough to be quiet then giving it some gas just to hear it revv up.. nothing like cruising around listening to a beautiful motor!

gaspam

11 mpg in city for me and 17.5 mpg on hwy (averaging 84mph)

clkwork

The dealer can test your injectors. Many of mine were out of spec (some were leaking) and I had them all replaced under warranty.