05tonkaf150

I own an 05 f-150 xlt 2wd with a 4.6. I gewt approximately 12.5 on average mpg. It doesnt matter whether I baby it or smash as it seems to do best right in between. I just turned 60k and run full synthetic, just replaced my air and fuel filters, and just put new spark plugs in it. This truck has been this way since I puchased it last year. It doesnt seem to have the power it should as I have driven other f-150's both 5.4 and 4.6 and they had way better power. Also in attempting it run a scanner to check the parameters to see if there was a possible misfire, the scanner doesn't read the ECM or anything at all. Running or not. I have been working on cars for quite some time and seem to be stumped. Can someone please steer me in the right direction.....I really dont want to go to the dealer for them just to tell me that nothing is wrong.

Mod (Ret.)

Does the scanner power up when you plug it into the OBD II port? If not, check the fuse for the center dash (below radio) cigarette (accessory) port, as the OBD II port and the center dash cigarette lighter share the same fuse; folks blow this fuse by plugging in an accessory that draws too much amperage.

If you are getting power, then I'll guess there are no codes being stored.

Do a search on fuel mileage. You'll see you are not alone. The 4.6 is the small V8, and it's "pushing" some heavy weight around. I have read that the 5.4's get from 12 to 19 MPG (city/highway). I assume that the 5.4 doesn't have to work as hard to move the truck as the 4.6.

I have the 4.2 V6 in my F150, and I do get an honest 17 to 20 MPG. Of course I don't have the power of your V8's, but I did not require it.

You did not mention if the truck has the stock tire size. Have the rims/tires been changed? A larger size can reflect gas mileage.

bluescrew

What made you suspect a miss fire? Have you had any specific symptoms which might be helpful for us to know?

05tonkaf150

Well to be hones with everything I am very aware of the size and power issues. I also own a 1967 f-250 with a 390 that gets 10 to 18 mpg with over 400hp on bigger tires, tller gears, and only a 3 speed. But if I am not using that power all the time.......should not make that much of a difference. Now I do run a tire size but the difference before and after was in my favor but not by much. Maybe .25mpg and yes they are bigger. 285\70r17. Thats what bothers me. Plus I also have a three inche level kit on it which should have killed mileage and did nothing except make it a little top heavy. To answer the other question, WAY to rough of on idle for a modular motor. Maybe if it was pushrod but not overhead cam.

fordmanforever

for a 2wd I thought you would get better fuel econ. my 05 4x4 only gets about 14.5 avg. with the 5.4. To be honest I used to be a Ford truck guy went to chevy came back to ford with this truck. I like the quality of the truck, however the engine power just is sad compared to the chevy counterpart. but I do love my truck. I would get it looked at maybe. Hopefully somone will chime in with an answer