The EGR doesn't reduce fuel mileage, nor does the pcv valve. (which is required for normal engine operation). Air/fuel ratio is a set value which doesn't vary much in a gasoline engine, so NOTHING you can do to the truck will increase fuel mileage signifigantly, except SLOW DOWN. Try decreasing your speed from 65 to 55 and you'll see a 3+mpg increase! It's physics.

Drive slower. That's the answer. Get an edge EVO, and you'll see it right in your face, the slower you go, (down to 40mph when o/d kicks out) your gas mileage increases. That being said, I suppose that a higher gearing in your rear axle could increase fuel mileage, (possibly signifigantly) but it will decrease performance.

So,.... Slow down, or change your gears, or both. But slowing down WILL yield the most.

 

Thanks for the advice, but the back roads I drive around here all have a speed limit of 55 MPH already, which I adhere to. --DIY

 

thats wierd we have the crapiest winter blend up here in ny and I get 15.5-16mpg on the winter blend here in my 99 f150 4.6 4x4 I fond a improvment in millage after changing my plugs wires and air filter for what its wrth when in doubt tun it up I say!

 

I have a 98 XLT 4.6 4x4 here in Va Beach and I am getting around 13-14 mpg in the city and around 16-17 on the highway. I drive pretty conservatively only to save gas...I usually average about 300 miles to the tank (when the low fuel light turns on) and usually only put in about 21.5 gallons. I also have a K&N FIPK 57 series and a Flowmaster single in dual out exhaust and I have 285/75R16 (which makes my speedo/odo 9.25% slow and my 300 miles per tank is after I have re-factored that 9.25% back in)

I think the key is keeping your foot out of the floor like Chester said.

 

im getting 15-16 MPG city on 01 5.4L Supercrew, I must be lucky!

 

16mpg city?You are being too easy on it
Thats what i get roughly on interstate.
City maybe 10 if i'm nice too it

 

Why would you do that?? That's your 'cold air intake' setup and cold air is better then hot air for an engine... Yeah, it's a small diameter hole to the outside, but it should be more then enough for the mods you have on your engine...

I've got a 97 5.4 with 170,000 miles on it and I get an average of 15 mpg with it... All city driving, the thing sucks the gas... All hwy, it can get up to 18 mpg..

Not that it's the same deal, but my wife drives a 2003 Rav4 and when she drives her 5 miles each way to the 'park and ride' she only gets about 18 mpg... When she drives it on the hwy for any distance, it gets 28 mpg....

Mitch

 

Yeah, I know it would help me a little to finish the job I started when modding the air box. I considered opening the hole in the fender up to be 3" in diameter and then using a rubber pipe union to go into the inner fender, but I haven't had the time to do so as of yet. I have a hard time believing this is the cause of my 4 MPG deficit over what it sounds like you're getting. And there are plenty of open element air intake kits out there that don't work any different than my current setup.--DIY

 

Warm air intakes do not reduce fuel mileage. Your computer adjusts to compensate for intake air temperature. It has (practically) no effect on fuel mileage whatsoever. So unless you somehow screwed up the MAF reading when you did your modification, that isn't your problem.

 

Yup, my sentiments exactly, and with the sub freezing temperatures we've had over the last months, I KNOW that's not a contributing factor. But yet again on my last tank I only got 11.4 MPG, and I didn't use my four wheel drive and I didn't really drive hard either. I guess I'm just due for a tune up. --DIY

 

I just filled up my 07,4x4 screw, 3.73 after the most stop and go plus towing my skiff around town for the bulk of this tank and got my worst round town mileage but it was still 13.69. I'm not happy about the swing because I was normally getting 15 or better. I guess I should be happy compared to 11.

TT

 

Had a '97 f150 S-cab off-road 4.6 auto 3:55's got 16-17 avg. traded it in on an 01 f150 4X4 5.4 S-Crew 3:55's got 11-12 avg. did pull a load better, but not a big difference without a load on the back
Now have an 01' Lariat 4X4 S-Crew Off-Road (swapped the decal's to FX-4) 4.6 3:55's. Been having it since '03 (78,000 when I picked it up) consistantly get 17 to 19 mpg. Most of my driving is back road 55mph roads, but I drive about 65-70mph. If I stay on the interstate @ 75mph I get over 19, but never have hit 20.

 

Probably not..... If you don't have any lights, everything's going purty good from an engine standpoint....

Try putting 50lbs of air in your tires. You'll probably see a small mpg increase.

 

Try having a lead foot and getting only 15 mpg in town and on interstate. The only way I have gotten anyn better is doing 55-65 on backroads, and then it is only about 20 mpg.

Hey Chester, I would try that but my tires are only rated for 45 psi.