[Ottawamalibu]

Hello I've just recently acquired a 2007 Maxx 6cyl 3.5l with 128,000 km on it. It's a great car however the fuel efficiency is terrible. Average 260km on a 60 litre tank. The car recently passed e-test and a quick overview from a mechanic including code reading that did not raise any red flags.

I know that efficency is shot in the cold snowy winter months but I can't think that this is normal. The DIC indicates that I should be able to get at least 390km on a full tank at 16.5l per 100 km.

Has anyone else experienced simillar issues, can anyone think of any solutions. I welcome your experience and expert opinions.

 

[Unfettered]

Yes. My '06 has the same issue. Fuel mileage is down about 20% from "normal". Seems worse this year, but it may be that I'm noticing it more as fuel prices rise.

Solutions would include not letting it sit and warm up, checking tire pressure, knocking any snow off the car as quickly as possible (snow buildup adds weight, weight decreases mileage), etc.

And welcome to the site.

 

[Northern Bu]

I asked about this on my previous car and the dealership told me that it was because in the winter time, the refineries switch to a winter blend for gasoline.

http://www.slate.com/id/2098672/

 

[Silver LTZ]

Check your plugs and wires. Plus, dump a bottle or two of a good fuel treatment in there. But as mentioned, "winter" gas is not as good.

 

[05ls]

Re: 2007 Maxx LTZ 6 cyl 3.5l fuel efficiency problem

Try cleaning the butterfly valve on the throttle body. Lotsa gunk gets in there from the line off the pcv. Also, don't run ethanol blended fuel - I like Shell Gold/VPower. Reading the factory manuals and inquiring with various gasoline retailers, I was not satisfied in any of their answers in how they test/regulate to maintain 10% or less ethanol. Ethanol over 10% will damage fuel pump seals and other components. Other reasons for poor gas mileage are longer warmups/idling. Also try electronic contact cleaner on your MAF sensor - could be a very easy fix.

 

[Ottawamalibu]

Thank you all for your feed back and ideas, sorry to get back so late on this as the holidays and illness has prevented me from coming back here. I plan to take your suggestions to my mechanic soon.