new owner with fuel question

[russell072009]

i have a 1997 with 65k on it. it has the 4.6. is it normal to be getting about 15 on the highway at 65 with cruise set? according to the instant economy meter that's about what i get. i also noticed that my truck hates overdrive. any kind of hill it decelerates and to maintain it has to downshift. also on slight uphill runs it will not shift in to overdrive on its own unless i flutter the throttle until it co operates. is this all normal for a 97 with a 4.6? i realize its a big truck but come on. i average about 14 MPG.

 

[fun2drum]

At fueleconomy.gov http://www.fueleconomy.gov/mpg/MPG.do?action=browseList they show a 97 4x4 with 4.6 as doing 14 mpg avg. I get about that avg with my 5.4 with mostly highway driving. I don't know about your OD problem, though. My OD does pretty well and only downshifts on the steeper hills.

 

[Jay87LX]

being that it is a 4.6 and a big truck I am sure it will want to come out of OD on an incline

 

[fiveohpoepoe]

You are doing well getting that mpg. I had the same issue with my 98 4.6 on any incline/hill. The only solution I know which cost wise would be too much for me, is to burn a chip to change the shift points or a higher gear.

 

[dougmcp]

Newer vehicles get better mileage but yours is 15 years old.
15mpg with a 4.6 is good at 65mph and they are a little weak on hills.

 

[russell072009]

Thanks people. I just wnated to make sure i didn't have any bad O2 sensors or anything.

 

[walnuts4x4]

sounds like its good to me... I would love 15s on the highway...lol but on long trips I can almost get 14...

 

[dougmcp]

Thanks people. I just wnated to make sure i didn't have any bad O2 sensors or anything.

If your O2 sensors act up, along with a bong, bong, you'll get one of these:

 

[russell072009]

If your O2 sensors act up, along with a bong, bong, you'll get one of these:

depends on how bad. I have seen sensors on their way out give problems but not throw a light.

 

[rburch]

Instant economy tells me that i get around 16 mpg at 70 but i dont think it is very reliable and i also have an intake. Mine also downshifts for hills. It just doesnt have the torque to pull the hills

And why does the instant economy start over every time i shut the truck off? Why doesnt it do like most others and do a constant average fuel economy?

 

[Thermo]

russell, what size tires are you running on your truck. That can have a big effect on when the truck will want to kick out of overdrive. Also, what gear ratio is in the back end of the truck. The 97's had the possibility of having a 3.31 rear end. Good for the flat highway, but sucked for any sort of hill. If you are not sure, take the truck up to 70 mph and tell me the RPMS of the truck. I will be able to tell you the gear ratio from there.

 

[russell072009]

And why does the instant economy start over every time i shut the truck off? Why doesnt it do like most others and do a constant average fuel economy?

mine has both. push the mode button 3 times from off to get total average and one ore for instant.

 

[rburch]

Thats what i meant. My average mpg starts over every time i shut off the truck. So i dont know what the average mpg is over a period of time, just trip to trip mpg.

 

[russell072009]

Thats what i meant. My average mpg starts over every time i shut off the truck. So i dont know what the average mpg is over a period of time, just trip to trip mpg.

sounds like a memory thing. not sure how it's wired but sounds like maybe a constant 12V memory wire is damaged.

 

[rburch]

So yours does that?

 

[dwinch82]

Hey all,

I am new here but I just made a long trip in my 01 expy with the 4.6L with a airaid intake and a aftermarket turbo muffler and I am getting about 21 miles to the gallon. Is it just me or is that really good for these trucks? It is a 2wd and it has about 140k on the clock.

On the first part of my trip I got 17.5 on the highway. Then my check engine light came on and I found a vaccum hose was off from when I changed the plugs. Put the hose back on and I am getting over 20 mpg now.

I bring up the vaccum leak because my cruise was doing the same thing in down shifting on not so steep hills. Got the leak taken care of and now it takes a pretty good incline to get the truck to downshift with the cruise on.

And my OD is just as stubborn as originally posted in the thread. Sometimes I have to play with the throttle a little bit to get the tranny to shift into OD. Don't know what the problem is yet.

David

 

[alaskanexpy]

your doing fantastic IMO! lol

 

[fun2drum]

dwinch, I don't think I could do that well if I were going down a steep grade with a 20 mph tail wind all the way.

 

[GAINMOB]

1st i've heard using the airaid intake...only seen them in the magz...

 

[fun2drum]

Is the AirAid what's boosting the mpg so much?