OK, so my 04 5.4 fx4 only has 38K miles on it and its getting terrible mileage. I get around 10.5-11 mpg on a normal tank and thats only about 260 miles or less before the damn light comes on. A few months ago I bought a brand new edge tuner and it gives the truck great power gains, but hasnt done crap for my mileage and im running it on level 2. I do mostly city driving and i know that last year when I bought the truck in july i could go at least 300 miles before the light came on. Any ideas?

 

Keep your foot out of it. Clean the MAF sensor. Get custom tuning.

I'm on 35s and average 13 city 16 highway.

 

buy a car or get used to bad mpg.

 

Have you done the air filter ,flow through exhaust and using synthetic oils throughout ?,

 

the best thing you can do is take your time. lighten up the foot, slow down, dont ride anyones bumper, dont race on the road, clean maf, clean or change air filter, change fuel filter. what kind of air fiter do you have? is the truck lifted? tires bigger than stock? what other aftermarket mods do you have other than the edge?

 

The truck has a k&n drop in filter and custom dual exhaust and brand new tires to factory specs. This may sound stupid, but how do i clean the MAF?

 

x2 ?

 

Assuming that yer truck has a tach, push the gas feed down enough that the tranny shifts at around 1800 rpms. No, you won't be ahead of traffic but the fuel mileage will go up. Make sure the tires are maxed out on pressure as stated on the sidewall of the tire for less rolling resistance. When approaching a traffic light or stop sign, let it coast to a stop. Synthetic lubes buys you nothing as those that would save you any fuel are already in the vehicle as factory fill. You might search for "hypermiling" on the net. These guys are getting over 100mpg out of cars already on the street- stock. It's all about knowing how to drive for fuel mileage and doing minor prep on the vehicle. FWIW, my 04 SCrew 4.6 gets 17-19 town, 21-24.5 hiway, and it's stock.

 

Mileage is all about the driver. If your getting bad MPGs adjust your driving habits.

 

You can also thank summer blend gas with ethanol.

 

Thats very true!

 

If you drive mostly city you'll have poor mileage. The only thing you can do is keep your foot out of it or get a custom gas mileage tune.

 

Really what did you expect out of a 6,000 lb truck? You want mileage get a car. I get 15-16 in town, if it all of a sudden dropped to 10 that means something is wrong. Did you start out higher and it dropped, or has it always been this way?

 

Engine mods like duals don't necessarily increase hp or gas mileage. If you over oil the k&N, it could crap up the MAF causing problems.
Lifting a truck decreases gas mileage. Larger, heavier tires decrease performance and gas mileage.
Your truck weighs a minimum of 5500 lbs. Consumes a lot of gas getting it going.

 

that filter is one possibl problem. the oil from the filter will get onto the maf causing false readings. whether its your problem or not, i dont know but its definately worth cleaning. pull the maf out and use maf cleaner or electrical cleaner that leaves no residue. but you mainly will have to work on your driving habits.