I just recenltly bought a 97 expo with the 5.4 and the 3.73 gears. This truck was a U.S. Border Patrol vehile in Texas. I can not get over 11.5 mpg and thats driving 45 miles round trip to work all highway going an even 70mph. I had my local Ford dealer check it out and they cant give me any suggestions. They say the only thing wrong is the O2 sensor on the passenger side behind the cat and this shouldnt affect it. This mileage is killing me but I love driving this beast. Any suggestions?

 

11.5 is about normal for most although after rereading your post, HWY MPG should be better than that. With a few modifications I get 13-14 around town and as good as 18-19 on the HWY and 11-12 towing 7000# plus. However, spending the $$ to do that and then pay for premium fuel to some folks isn't worth it. I like the extra "fun" in driving it and the extra power and grunt for towing.

Also the '97 5.4 is the lower power 5.4 so it's likely to work harder to move it around. In '99 the 5.4 got the PI heads and a pretty good power increase.

Try dropping your speed to 60 MPH and see what the milage does. I've got the 3.55 rear and about 70-75 is where MPG starts to drop quick. Also, any head wind drops mine like a rock. 2 MPG into a pretty good head wind isn't unusual.

By the way, welcome to the boards!

 

FamilyRide is right. I have a '97 Expy with a 5.4 and 3.73's in the rear end. If I want decent gas mileage, I keep the rpm's under 2000 on the highway. I have 17" wheels so that's around 65mph. Make sure your air filter is clean and your tire pressure is right and you should get around 12mpg city and 16-18mpg on the highway. It is possible to get better than that as FamilyRide said if you have a 30mph tailwind it really helps.

 

I did a 500 mile round trip yesterday to pick up my boat. So about 250 unloaded and 250 loaded (boat about 7000# yesterday).

On the way down I ran the speed limit and got there at 18.1 MPG on the overhead and 18.6 MPG by calculation.

On the way back, loaded and with stong gusty winds (that front came through) and running the speed limit again (where I could) MPG was of course much worse. I calc'd the trip overall so I got home with 13 MPG on the overhead and 12.7 MPG by calculation. A rare thing, I actually had to slow down a few times when the crosswinds got real bad and run about 60. Winds were gusting to 30-35 MPH.

Another difference was about 70 degrees and humid (even some rain and fog) on the way down, and 50's into the 40's on the way back.

I know from other trips what I get when I'm driving certain RPM's loaded and unloaded and I think yesterday with the conditions and the speed I may have actually been getting the worse MPG towing I ever have. However, I know that from 55 to 60, then 60 65 then 65 to 70 I can go from drop 1-2 MPG starting at about 13 and start sinking quick. I watch yesterday and saw that running about 1800 RPM I did pretty well. At about 2000 RPM I could see MPG start to drop. 1500-1800 is alos a good strong range to run too. I can usually pull a hill down and hold 60 in OD. It will actually hold OD down to about 1100-1200 RPM as long as I don't stick my toe in it.

Oh, I filled up the night before I left, then topped her off before heading back and then filled her up when I got home! At $1.78...ouch! About $75 in fuel.

 

Family Ride,

Getting to the point where the boat is cheaper to fill and run than the Expy................

 

sheriffdep, maybe you should find a measured mile and check the odometer. If larger tires are on it now, you may be doing better than is indicated on the clock.

 

LOL, actualy, after the work I just had done to the boat, she's a little thirstier. But can STILL run all 65 gallons of 87 octane!

 

I see the list of toys for the Expy hasn't gotten any longer...Shift the emphasis to the Sea-Ray? Have you run it down to the Gulf for a weekend?

I'm currently getting an intermittent ABS light that results in pedal inputs when braking, but when the lights off, you don't feel it. Awww, she must miss the smell of new leather from her 03 cousins at the dealer and wants a trip to visit.

 

No salt for me! North Texas stock tanks only. Well, except for the trips to real lakes like Ouchita and Table Rock.

Yep, I just had some engine work done as well as adding Corsa CC, labbed props etc. Now she matches the attitude of my modded SUV. A modded SUV on the water! But I have to say, the SR sounds a WHOLE lot different. Something about an unbaffled open exhaust big block with a little attitiude. It was fairly mild work, but the cam actually gave her a little lope that we didn't expect. Kept the crappy OEM GM MPI so we got stuck at about 375 HP. Now I'm hoping for it to get just warm enough to get her out for the maiden voyage! Maybe this weekend.

Of course that doesn't touch the kind of power being made in boats down in your neck of the woods!

 

Here in the Banana Republic we offer 3 classes of boats and their owners:

18' Open Bass Boats with a 250HP V6 Johnson and throttle settings of Idle(55mph) and Open(75mph) to race all the other "fisherman" who are out at 5am to that one "sweet spot" on the lake.

21' + up "Cigarette" go fast boats who can (1) create 5' wakes in the "no wake" zones (bonus points for doing it at night with no running lights) of the interwaterways, or (2) foolishly think they can outrun Customs helicopters who have 50 calibre sniper rifles (with sniper) on board as they dump their "load" overboard making the 11 p.m. news with the provided video clip, or (3) idle up and down the intercoastal on Sunday's with some "arm candy" sunning on the deck while us "Dad's" try not to get smacked for staring (experienced dad's always wear mirror coated sunglasses)....

and finally:

You have the Cabin Cruiser owner who after realizing the TRUE costs of boat ownership (particulary during divorce) decides to do the "Hatitian Shuffle" and sneak in 30 or more per trip.

Ah, life in the Sunshine State!

 

I am driving a 99 5.4L LLS rear. I was getting pretty lousy mileage also. I have put in a superchip tuned by JDM engineering, JDM electric fan kit, K&N filter (for stock replacement), along with the Cobra water pump. My mileage has increased from 13mpg to 19mpg. The only down fall is having to run super unleaded. But the gas mileage still outways the cost difference.

 

Johnny,

Couple of questions. What mod do you think makes the biggest difference in MPG? How much do you think you've layed out in dollars for all the toys? How much of an improvement in performance?

Thanks,

Keith

 

I think my best gain was the chip. But the fan freed up around 18 hp with at least 2mpg gain. I wish i would have dyno it first then after. But as for the price here is where i get my goody's from. They are pretty good people JDM Engineeringhttp://www.svtperformance.com/forums/forumdisplay.php?s=&forumid=55
And i got alot of get up and go when i hit the gas now. I plan on messing up my gas mileage by putting in the 4:10 gears soon.

 

Family ride I need what you have .. MY wifes 2000 expy with a 4.6 4x4 sucks and my SD gets less even when I pull my 23ft W/A 7000# if your ride gets that kind of milage pulling, mabe i should replace the V10 with your 5.4

 

LOL, I have to admit I'm pretty pleased. I know many people that tow with the same thing, bone stock, and get 9-10 MPG and tow much smaller boats.