Notices
2004 - 2008 F150 2004, 2005, 2006, 2007 and 2008 Ford F150's with 5.4 V8, 4.6 V8 engine
Sponsored by:
Sponsored by:

MPG fall off after modifications

Thread Tools
 
Search this Thread
 
Old Oct 12, 2010 | 07:30 PM
  #1  
2005f15054liter's Avatar
2005f15054liter
Thread Starter
|
New User
Joined: Oct 2010
Posts: 3
Likes: 0
Question MPG fall off after modifications

I installed a K&N Filter and a hypertech programer on and everything was pretty good. About 19hwy mpg. I installed megaflow true duels and now my mpg is around 15 mpg. Any ideas?

I have found a supercharger from a 2004 lightning I can buy cheap. A mech. told me this would solve my problem, any thoughts?
 
Reply
Old Oct 12, 2010 | 08:06 PM
  #2  
bridge's Avatar
bridge
Sick 'n Tired
Joined: May 2006
Posts: 2,969
Likes: 47
From: League City, TX
Club FTE Gold Member
1) I don't a supercharger off an 04 Lightning (heritage) will fit on an 04 3V engine. I think the intake manifolds are different? If you want a supercharger Roush makes one, but don't expect any significant increases in mileage.
2) If you've paid to make your rig go fast and you've given yourself a lead foot your MPG will drop drastically.
 
Reply
Old Oct 12, 2010 | 08:22 PM
  #3  
magnet1's Avatar
magnet1
Senior User
Joined: Aug 2008
Posts: 278
Likes: 1
From: Bethlehem, PA
Super charger takes horsepower to make horsepower. I would think mileage would be going even more down hill with this upgrade.
 
Reply
Old Oct 12, 2010 | 08:26 PM
  #4  
Coskid's Avatar
Coskid
Postmaster
Joined: Jul 2010
Posts: 3,743
Likes: 2
From: Henrico, VA
How long has the duals been on and do you still rev it some to hear the growl from under the truck? This is usually one spot that kills MPG after that MOD.

Also if you want to get MPG up the best thing you could do is buy a tuner for your truck.
 
Reply
Old Oct 13, 2010 | 05:35 AM
  #5  
shotgunz's Avatar
shotgunz
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
Originally Posted by 2005f15054liter
I installed a K&N Filter and a hypertech programer on and everything was pretty good. About 19hwy mpg. I installed megaflow true duels and now my mpg is around 15 mpg. Any ideas?

I have found a supercharger from a 2004 lightning I can buy cheap. A mech. told me this would solve my problem, any thoughts?
Originally Posted by Coskid
Also if you want to get MPG up the best thing you could do is buy a tuner for your truck.
kid - he has a hypercrap tuner.

Did you install a drop in filter or an aftermarket intake system? Did you mess with the MAF when you installed it? Did you over oil the filter? Have you cleaned the MAF?

What tuner did you buy (model)? What tune are you running? Are these hand calculated MPGs or lie-o-meter? Where do you live? Are you using the winter blend gas?

MPG can be afected by a lot of different variables. We need more information.
 
Reply
Old Oct 13, 2010 | 08:20 AM
  #6  
shakin's Avatar
shakin
New User
Joined: Dec 2009
Posts: 3
Likes: 0
From: Towanda PA
Originally Posted by magnet1
Super charger takes horsepower to make horsepower. I would think mileage would be going even more down hill with this upgrade.
You are right in a sense. But, no matter how you slice it, it gives you a LARGE gain, and will show no signs of loss in power. And if a driver can drive for mileage the same as they did before a supercharger they will gain mileage.
 
Reply
Old Oct 13, 2010 | 10:30 AM
  #7  
Coskid's Avatar
Coskid
Postmaster
Joined: Jul 2010
Posts: 3,743
Likes: 2
From: Henrico, VA
[quote=shotgunz;9433701]kid - he has a hypercrap tuner.\quote]

Oops I missed that one thanks for pointing it out shotgunz.
 
Reply
Old Oct 13, 2010 | 04:46 PM
  #8  
2005f15054liter's Avatar
2005f15054liter
Thread Starter
|
New User
Joined: Oct 2010
Posts: 3
Likes: 0
To answer you Shotgunz, It was a drop in Air filter and I didn't mess with the MAF, and I haven't cleaned it. Programer is a hypertech IV. I was told that the reason MPG fell was because the 5.4 Liter needs the back pressure, any thoughts on that? One more note, every sence the mega flow, the truck has lost power along with MPG. before it had a lot more pep. MPG is based on figures not the information center, even though most of the time it is pretty close to the same. I am running the 87 octane Program, as far as gas goes I usually run 89, winter blend? What ever they have in the pump.

Also, I do not get on it more to hear the pipes, actually I don't like the way it sounds, it is to loud now. I drive it the same now as I always did.

Thanks for your replies, I am just trying to figure this thing out. With out removing thing I paid good money for.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

 Verdad Gallardo
story-1

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-2

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-3

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-4

Every 2026 Ford Engine Explained

 Brett Foote
story-5

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-6

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-7

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-8

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-9

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
Old Oct 13, 2010 | 04:59 PM
  #9  
shotgunz's Avatar
shotgunz
Posting Guru
Joined: Nov 2009
Posts: 2,016
Likes: 3
From: NC
Usually exhaust systems will affect hp and low end torque, but not enough to explain a 25% drop in MPG. I'm not familiar with the megaflow true dual setup. Is this a cat back system? Are the factory cats still on? Have you changed the O2 sensors?

Any codes? Your hypertech should be able to read them.

Most canned tuners are designed for stock trucks (including cat-back exhaust systems and drop in filters). Have you tried setting the truck back to stock?

When was the last tune-up? COPS changed? Have you cleaned the throttle body, fuel filter, and MAF?

Any other changes to the truck?
 
Reply
Old Oct 13, 2010 | 05:19 PM
  #10  
2005f15054liter's Avatar
2005f15054liter
Thread Starter
|
New User
Joined: Oct 2010
Posts: 3
Likes: 0
Yes, the factory cats are still on there, last tune up 8 months ago, I have ran different types of fuel system cleaner through it. I haven't cleaned the MAF or fuel filter. I did switch it back to stock for a day or two, didn't really notice a big difference. I could try it for a full fuel load if you think it may make a difference. HAve not changed the O2 sensors. I have no error codes. COPS?
 
Reply
Old Oct 13, 2010 | 05:37 PM
  #11  
bridge's Avatar
bridge
Sick 'n Tired
Joined: May 2006
Posts: 2,969
Likes: 47
From: League City, TX
Club FTE Gold Member
I've pretty much gotten 12-13 mpg since new and after adding programmer, air intake and magnaflow cat-back. See this post for my results. https://www.ford-trucks.com/forums/6...g-results.html

Outside of a dirty fuel or air filter you must have something else going on to explain the decrease. My guess is the programmer has messed with your timing/air/fuel ratio. Make sure your tune is the 87 octane tune. If you're running 87 on a 93 tune you could get incomplete combustion and could damage the cats. This would also reduce overall power.

You should return it to the stock tune and see if your mileage returns. I've never heard of a cat back system causing a loss in MPG (my results have been steady) and I don't see how back pressure, or lack thereof would cause a decrease in MPG/power.

Once last thing; 15-16mpg hwy is about normal for these trucks if you're running 10% ethanol. You might want to see if your local filling station recently changed over to E10.
 
Reply
Old Oct 13, 2010 | 06:29 PM
  #12  
1bad67sbf's Avatar
1bad67sbf
Posting Guru
Joined: Mar 2010
Posts: 1,173
Likes: 0
From: northern va
my 07 truck gets about 15-16 mpg and i got 16-17 mpg before the 35in tires. if the loss in power came shortly after exhaust job than i would stay in that area the most and one option would be have an x-pipe or h-pipe installed and maybe that will help your problem but it should also help if you dont like the way it sounds now. (what if they did not get a good seal when they put the new exhaust on and extra air was on the o2's and made them think lean, so the truck bumped the fuel up to make up for it?)
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
kenn_rosie
6.4L Power Stroke Diesel
1
Apr 27, 2013 02:11 PM
Mrfun2fly
6.0L Power Stroke Diesel
37
Jan 29, 2010 05:50 PM
Cpuslayer
1983 - 2012 Ranger & B-Series
7
Feb 14, 2008 08:54 PM
knolltkford
1999 - 2003 7.3L Power Stroke Diesel
4
Mar 24, 2007 10:49 PM
cmcmeans
6.0L Power Stroke Diesel
23
Aug 30, 2006 01:14 PM




All times are GMT -5. The time now is 02:10 PM.

story-0
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Slideshow: The VelociRaptor Expedition gains a lift, upgraded suspension, Brembo brakes, and trail-ready equipment while retaining the stock 440-horsepower EcoBoost V6.

By Verdad Gallardo | 2026-06-12 11:01:55


VIEW MORE
story-1
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-2
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-3
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-4
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-5
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-6
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-7
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-8
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-9
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE