My 98 F150 4.6 4X4 EXT. Cab I have had this truck about 2 months and have only been getting 10-11 MPG in the city. I have replaced the the fuel filter,PCV valve,and getting ready to put a K&N air filter in. There are know check engine lights on and it seems to run good with 65,000 miles on it stock tires original size 17" It is just bugging me to death knowing I should get better out of this 4.6 Auto trans. and 355ls gears. I went 216 miles agas gauge was right under 1/4 tank. Does this sound right? I have been thinking about a Super Chip if they will help with H.P. which might ease up on the gas pedal. I dont know much about Fords but I love this truck but surely I should be able to get beeter than 10MPG, shouldnt I?

 

sounds about right. My 98 v6 got about that. You said you were a little under 1/4 right?? You have a bit to go still. I say 320-340 as i got and about the same for you.

 

I have a 2001 Scab 4.6, with a 3:08 rear end I got 17mpg, after I put a 3:73 rear end in, I got 16mpg. My superchip didn't seem to make much difference. I think that with a chip you might be more inclined to put the pedal down a little quicker and a little farther, which would decrease your mpg. I think you should be closer to 14 in the city. A tune up might be in order.

 

I had a similar situation so I decided to change my plugs and wires. I could not believe the difference it made. My mpg went up from 11-12 to 12-13. I also found some of the lost H.P. I had lost over a five year period.

Ford claims you can go 100K without changing plugs but there is no way mine would have gone that long.


Rocks

 

Hi Ranger 451,

Glad you dropped by!

First, *never* attempt to estimate your fuel mileage by where the needle on the gauge is in these vehicles, that is never the way to calculate fuel mileage correclty, it's just not accurate enough. You have no idea what's actually in the tank when the needle is pointing anywhere on that gauge, at least, not until you've owned it for long enough to have put enough miles on it to have filled it up enough times at different fuel levels to actually get a good feel for that, and that will never be accurate anyway, so just do it right and get an accurate number. You do that by filling the tank until the pump first shufts off (the first "click," don't top off ever), and dividing the number of miles you drove since the last fill up (with your trip odometer) by the number of gallons it took to refill it. That is the only way to ever calculate gas mileage accurately in any vehicle, but especially these F-150's due to their non-linear gas gauge.

The Superchip will certainly help in the power department, it's teh signle best bang for the buck actually, and your highway mpg will probably go up too. However, you're not going to be able to spend less money overall for gasoline by using the Superchip, as it requires premium gasoline of 91 octane or higher. We can make a Superchip for you that only requries 87 octane, but you won't see much power gain from it, maybe 3-5 HP on a 4.6 engine. To get more pwoer via tuning (powertrain programming), you have to tune the engine for good quality fuel of at least 91 octane.

10-11 mpg in the city is about par for the course with a big heavy 4X4 being hauled around by a little 4.6 motor, as you've got well over 2.5 tons of truck there! I'd say you're doing "OK" there mileage wise, but that certainly *can* be improved with the right modifications.

What I would do is give us a call so we can go over with you in detail what will really help you the most with your vehicle in your situation, which are the ignition upgrades that 03Lightninrocks mentioned in his post, & converting over to electric fans. With those mods, you can pick up an easy 30+ HP *and* 1-2 more mpg as well, very significant improvements in both power and fuel mileage.

Our contact info is below if you'd like to go over this in proper detail to explore all your options, etc., & good luck with your truck!

 

I've gotten as poor as 11 mpg city driving in my 4.6. That's stop and go traffic. I've also gotten around 18 mpg on a road trip up to the mounts. There are so many variables, it's hard to say whether the chip helps or not. I have noticed a minute change for the better with my trad. chip, flows, and K&N Fipk. We have to remember that we own V8's. The chip does improve the ride, acceleration and tranny shift in our trucks. If you ask me, I think it is a worthwhile mod. talk to Mike.