mpg question - Ford F150 Forum - Community of Ford Truck Fans

Go Back   Ford F150 Forum - Community of Ford Truck Fans > Late Model F150s > 1997 - 2003 Ford F150
Log In 


mpg question

Reply
 
 
 
 
Thread Tools Search this Thread
Old 04-29-2014, 08:34 PM   #1
Senior Member
 
cody5127's Avatar
 
Join Date: Mar 2012
Location: des moines ia
Posts: 788
Thanked 9 Times in 9 Posts
Feedback Score: 0 reviews
Default mpg question

OK, my 2000 f150 with the 5.4 4x4 is getting 10mpg. I know that's crazy low since I drive 80% Highway. Stock ride height, stock size tires, 265/70/17 running 35psi, I baby it a majority of the time. Don't have any cel codes, minus the 02 sensor.

Things wrong with my truck: exhaust leak at the passenger manifold, no cats. I know it should still be better than 10mpg.

Any tips on fixing the manifold? It's my only vehicle and I'd like to get it done in one day or less.
__________________
2000 f150 4x4 5.4 triton. Bone stock, soon gonna change.
cody5127 is offline   Reply With Quote
Join F150 Forum

Join F150Forum.com Today - It's Totally Free!

Are you a Ford F150 fan? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's a great place for Ford F150 Fans to meet online.
Once you join you'll be able to post messages, upload pictures of your truck, and have a great time with other Ford F150 fans. Whether your an old timer or just bought your F150 you'll find that F150Forum.com is a great community to join. Best of all it's totally free!

Join F150Forum.com Today! - Click Here JOIN FOR FREE


-->
Old 04-29-2014, 11:02 PM   #2
Senior Member
 
Join Date: Sep 2011
Posts: 6,432
Thanked 342 Times in 335 Posts
Feedback Score: 0 reviews
Default

It is probably running extremly rich due the exhaust leak along with bad oxygen sensors.
Carcrazygts2 is offline   Reply With Quote
Old 04-29-2014, 11:10 PM   #3
Senior Member
 
cody5127's Avatar
 
Join Date: Mar 2012
Location: des moines ia
Posts: 788
Thanked 9 Times in 9 Posts
Feedback Score: 0 reviews
Default

Wouldn't that make it run lean?
__________________
2000 f150 4x4 5.4 triton. Bone stock, soon gonna change.
cody5127 is offline   Reply With Quote
Old 04-29-2014, 11:26 PM   #4
Senior Member
5 Year Member
 
charliedyal's Avatar
 
Join Date: May 2009
Location: Tallahassee, Fl
Posts: 2,809
Thanked 129 Times in 120 Posts
Feedback Score: 0 reviews
Default

1. Replace the manifold if its cracked. Careful with the bolts, they break off in the head easily. Soak them with PB blaster the day before you pull them.

2. Replace your front o2's if bad

3. Get a tuner (SCT from MPT includes custom tunes) and disconnect rear o2's if you have no cats. They can make a custom tune for the deleted o2's.

Guaranteed you'll pick up 3-5 mpgs at a minimum.

Also, your current issues will cause it to run rich. Listen to carcrazygts2. Dude is solid.
charliedyal is offline   Reply With Quote
Old 04-30-2014, 12:14 AM   #5
Senior Member
 
Join Date: Sep 2011
Posts: 6,432
Thanked 342 Times in 335 Posts
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by cody5127 View Post
Wouldn't that make it run lean?
No because under load a exhaust leak will create a vacuum and suck fresh air making the PCM think that there is more oxygen in the system that there actually is. So the PCM adds fuel.
Carcrazygts2 is offline   Reply With Quote
The Following User Says Thank You to Carcrazygts2 For This Useful Post:
cody5127 (04-30-2014)
Old 04-30-2014, 05:26 AM   #6
Senior Member
 
cody5127's Avatar
 
Join Date: Mar 2012
Location: des moines ia
Posts: 788
Thanked 9 Times in 9 Posts
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by Carcrazygts2 View Post

No because under load a exhaust leak will create a vacuum and suck fresh air making the PCM think that there is more oxygen in the system that there actually is. So the PCM adds fuel.
Ah. Thanks for explaining.

I'm actually considering having a shop fix the mani leak. I know it's just the gasket as I've seen a chunk of it hanging out when I had it up on the lift at work. I just don't want to break a bolt off in the head and screw myself. Shop rates are around 230 bucks a side.
__________________
2000 f150 4x4 5.4 triton. Bone stock, soon gonna change.
cody5127 is offline   Reply With Quote
Old 04-30-2014, 10:32 AM   #7
Junior Member
 
Join Date: Apr 2014
Posts: 20
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
Default

Depending on the condition of the exhaust studs you may have to replace them. Ive seem them rusty and snapped before a wrench ever hit it.
dirtracr95 is offline   Reply With Quote
Old 04-30-2014, 10:38 AM   #8
Senior Member
 
Join Date: Sep 2013
Location: New Brunswick/Alberta
Posts: 761
Thanked 68 Times in 61 Posts
Feedback Score: 0 reviews
Default

I'd get a shop to do the manifolds. It's a bastard job most of the time and I'd rather someone else do it honestly because it downright sucks.
sportster07 is offline   Reply With Quote
 
 
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


All times are GMT -4. The time now is 12:05 PM.


Copyright 2006 - 20011 F150forum.com
This site is in no way affiliated with the Ford Motor Company.