Just bought a 2006 F150 STX 2wd with 45k miles. It has 5.4 engine & 3.55 rear axle. It's getting 10 mpg!!! Took it back to the Ford dealer and was told the 3.55 combined with short trips (6 miles one way) would cause poor gas mileage.

What can I do to improve the mpg?

 

I tried a cold air intake and catback exhaust and they did nothing to improve short trips MPGs.

I drive 4 miles to work one way. I have 2004 FX4 4x4 5.4 3.73 gears and I get 11.5 mpg right now in the winter. In summer, it's 12.5 to 13 mpgs.

 

6 miles to work is the largest factor as the engine is just barely warmed up but give it more break in time and it will improve somewhat,but it will be hard to get a lot more than that. 14-15mpg town seems to be the max.
jim

 

Now that I am used to it, I am getting 14.5 mpg. avg. with my '06 F150 4.6L std. cab long bed. I have an 8 mile commute to work, and most of my driving is in town. I do not put my foot in it too much, tho I am usually at least 5 over what ever the speed limit is. I figure the mileage may go up slightly when we get off the 'winter blend' we get this time of the year.

I will probably try opening up the airbox a bit and using a low restriction filter, as some here have tried, but I don't see spending a lot of $$ to chase a couple of mpg. Face it, these are big vehicles.

Mike

1963 F100
1986 E350
1997 Ranger
2006 F150

 

Right now with the winter blend gas and cold weather in S.Jersey, I average 11.5 mpg,'05 FX4, 5.4 W/373"s. Warming the truck up in the mornings for about 5 minutes doesn't help fuel econ. much either. Takes 10 minutes to get to work in the morning, all stop and go.

 

I never thought they put the 5.4 in the STX trucks...

 

Well how is your driving habits like to nail the gas pedal try keepin it under 2000 rpms the whole time and braking early proper tire pressure and size and tuned engine is the key to good mpgs but 10 is pretty low it should get at least 12-16

 

My opinion

You're not driving far enough for the engine to really reach normal operating temperature. If so, the computer will keep the mixture rich so the engine will run (kinda like driving with a choke on with a carborator). Ex: I have a 2005 SCAB 4x4 5.4. If I drive to one of my offices 20 miles from my home, I get 14-15mpg. If I drive to another which is 35 miles, I am up to 16. If I have to go to the far one, 70 miles, I'm up to 18. All this is in the same traffic flows, same acceleration habits, cargo weight, etc.

So, it doesn't matter what mods you do, or how you drive. The only way you're going to get better mileage is to not drive a truck that short distance.

 

i drive 10 mile trips every day to and from work then to the gym and home and i am getting 16.5 consistently and that was in the winter. I'm easy on the gas and i let the tranny shift up through the gears into OD before i get on the gas to hard but you should get better than 10 mpg...

last summer i was getting 17 to 18 with the same driving and i have 3.75 gears with a 5.4L and 18" wheels...

 

yep, 2006? it was introduced.

OP: I feel your pain, but as mentioned, the computer is still in a "closed loop" mode until up to operating temps...try for longer drive periods...although that would probably give the same result

damned if you do, damned if you don't

 

Jodeben: tim2003expy is absolutely correct. The driving tips others suggested will help too, as well as tire pressures. Strange as it sounds, you might consider an engine (block) heater, especially if you live in a cold winter area. Put it on a timer to come on a coupla hours before you go to work. The engine will then be half warmed up when you take off and the EFI won't be in open loop (and enriched) half the way to work. Or, on cold mornings, you might also cover part of your radiator to partially block airflow and help it warm up faster. Also, run a 0W-20 synthetic or 5W-20 semi-syn oil, it will reduce internal friction while the engine is cold. Performance air filters and such won't help you mpg-wise driving easy and slow in town. Bottom line on this, you are going to be proactive: No easy or lazy ways out of this, I don't think. Short hops just suck from your truck's POV.