Curious... For those of you with the 5.4 whether you have the 3.55 or 3.73 rear end, what are you getting for mileage? City, highway or combined?

 

I have the 3.55s. With K&N drop in only, I would get about 13.5 average. about 16 on hwy. I now have the Evo and am getting about 2.5 MPGs better on each.

 

What's an Evo? Do you have a link?

 

Interesting. I'm still on my original tank since purchasing and it's averaging 16 which is combined city/highway. Have 3.55 LS. I don't have a lead foot if that makes any difference.

 

No tuners out yet for the 2009's...

 

They are programmers for your vehicle. Through your vehicle's computer they change the parameters in which the engine will perform versus the factory settings.

Here is a link.

http://www.edgeproducts.com/product.php?pk=54&pvk=161

I have never used one myself as there was no need. You also need to be careful as it might give a dealer an excuse to say your warranty is void. It has been discussed on this forum but since I have no plans to use one I did not pay much attention to the posts.

 

I have 373 gears and 5000mi i have been getting an average between 16.5 to 18.5 mixed city and highway.

 

I have 373 gears and 5000mi i have been getting an average between 16.5 to 18.5 mixed city and highway.

 

I have 373 gears and 5000mi i have been getting an average between 16.5 to 18.5 mixed city and highway.

 

I have the 3.55LS and i am getting average of 18mpg.

 

Finished a 2330 mile trip in my FX4 screw from N. Cal thru Palm Springs-Phoenix-Las Vegas-Reno-Home, Hiway speeds generally 70-75mph, got about 18 mpg for the trip. Nicest long distance vehicle I've ever owned.

 

I have the 3:55 LS. During the first 2500-3000 miles my average was somewhere around 11.5 mpg, needless to say I was a little disappointed. However, now my average has jumped up to around 16 mpg . I usually drive with a heavy foot so I'm sure I could get better results if I eased up a bit.

 

I forgot to mention that I'm also running 33" BFG mud terrains and have 4 wheel drive.

 

Were you loaded down or towing a trailer on this trip?

 

Sounds like many of you are getting some pretty decent mileage out of these new 09's.

I know with my previous truck (05 w/5.4 and 3.73 LS) I never saw 18 mpg highway ever and city/highway combined usually was in the 14-15 mpg range.

I imagine the 4.6 may be even be slightly better, but I still like this new 5.4.