code P0171 - Ford Truck Enthusiasts Forums



Modular V10 (6.8l) SPONSORED BY:

code P0171

Reply
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 07-05-2014, 12:41 PM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 161
wendal is starting off with a positive reputation.
code P0171

I just bought this 99 f250 super duty with 197k.
I changed all fluids and installed new spark plugs. I then changed the exhaust. I deleted the cat and replaced my muffler with a glass pack. Right after that I got a P0171. The pickup runs rough and jerks when driving it.
I cleaned the MAF sensor. I did replace the fuel filter. I check the pvc hose under the throttle body. It looks good.
What other hoses do I need to look at for vacuum leaks? I have read that it may be my O2 sensor.
It ran pretty good until I changed the exhaust. I did add some marvel mystery oil at the same time.
I did clear the code but still runs rough.
Another problem
My 4x4 light, service engine light does not come on when I turn the key on. All my other light come on then go off. My check engine light never comes on either.
My ABS light is on but I know what the problem is their. The left front wire going to the sensor is broke.

thanks for any help
Reply With Quote
  #2  
Old 07-06-2014, 11:24 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 36,746
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
Something's making it run lean.

Start by checking the fuel pressure, and make sure it's 28-30 at idle, and 38-40 with the vacuum disconnected from the fuel pressure regulator.

Any chance you have an exhaust leak ahead of the O2 sensors?
Reply With Quote
  #3  
Old 07-06-2014, 02:35 PM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 161
wendal is starting off with a positive reputation.
I will look into the fuel pressure.
I will look at the exhaust but I did not here anything.
thanks again for the help
Reply With Quote
  #4  
Old 07-07-2014, 06:53 AM
CPaulsen's Avatar
CPaulsen CPaulsen is offline
Senior User
 
Join Date: Apr 2011
Location: Southern Oregon
Posts: 362
CPaulsen is gaining momentum as a positive member of FTE.
Check the vacuum hoses on both valve covers.
Reply With Quote
  #5  
Old 07-07-2014, 07:40 AM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 161
wendal is starting off with a positive reputation.
OK will do.
On the passenger side does the hose crack under the insulation? Can I cut it off and then zippy tie it back on?
Reply With Quote
  #6  
Old 07-09-2014, 04:37 PM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 161
wendal is starting off with a positive reputation.
OK I am sorry for the stupid question but where is the fuel pressure regulator?
thanks
Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
P1633,0500,0171,and 0172 acm05fsu 1997 - 2003 F150 13 12-04-2013 08:46 AM
03 Expedition: Codes P2195, P2197 and P0171 MCGA Expedition & Navigator 10 07-23-2012 11:21 PM
Engine Code Help P2196, _2197 and P0171 MCGA Modular V8 (4.6L, 5.4L) 5 04-04-2012 02:23 PM
P0171 and P0174 2000Ford2000 Modular V8 (4.6L, 5.4L) 10 12-03-2011 09:08 PM
Intake Plenum Gaskets Codes P0171 & P0174 Gulliver Ranger & B-Series 13 03-21-2010 11:34 PM


Go Back   Ford Truck Enthusiasts Forums >

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 On
Pingbacks are On
Refbacks are On

Forum Jump


All times are GMT -5. The time now is 05:24 PM.


This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.