Im new to the forum so I hope you guys can help me. I just bought a 97 f-150 4x4 lariat SC with 70K. The last owner was in his sixties and I dont think he dogged it. I am getting between 12-14 mpg. He said that he got 18-20. The truck did set up for a while with little or no use. I have put on a cold air intake which helped a little with HP but no help on the MPG. The truck has a problem with small hills in overdrive (kicking down). I have also put on new fuel filter and changed the oil and filter. Also new O2 sensors. Could the CATs be blocked up? Is anyone else having this kind of problem? One strange thing I have noticed is that the truck will warm up on a cold morrning very fast, like in about 10 bocks, blowing hot air. The truck does not overheat or anything like that after. I sure could use some help.

 

firedog,
Before installing the cold air intake did you disconnect the negative battery terminal? You need to reset the computer after you install aftermarket equipment to have the computer relearn the new settings.
Try that and see if your mileage improves, also consider cleaning the MAS (mass air flow sensor) You can do a search for directions, it's easy to clean.

Good luck

 

Yes I had the neg batter cable off the hole time I was installing the cold air intake (1/2 hr). I had the air sensor in my hand and it didnt look dirty at all. Is it something that cant be seen?

 

You can see the two silver diode like sensors when you look into the MAF unti, I spray mine down with Brake Kleen and let it air dry. I repeat until they are silver and shiny. As far as other thoughts go, I'm at a loss at the moment.

 

THAT TRUCK IS RATED I BELIEVE 13 CITY 17 HWY

It is very possible the previous owner exaggerated mpg.

I have owned ford, dodge and chevy extended cab 4x4s, the best mileage i got was with the z71 at 16mpg, but it had high gears in it and was a plug

my dodge got around 12, low gears pulled a lot better. that is 12 with a tailwind.

 

My 01 4x4 5.4L gets between 12 and 14. Which is much better than my 77 2wd with a mild 460 that gets about 6, but that 550 lb-ft of torque sure does pull good!!!

 

exactly what i am talking about...i currently own 2003 supercrew 2wd 5.4ltr 3.55LS rear .My best tank...best tank was 19...so far it only happened once with 16k miles on truck, i had it since it had 5 miles on it. It averages 16-17 mpg, worst was 12 (towing)

i do hear stories about fullsize v8 4x4 trucks getting 20+ mpg

BS

a fullsize 4x4 with v8 getting 15 mpg day in day out, every tank is doing good

getting 20, maybe with a diesel, maaayyyyyybe, but i doubt it. this may start many to come running claiming they get 30mpg in a one ton dually 4x4 with 38 swampers traveling at 85 mph BS