code P0171 - Ford Truck Enthusiasts Forums



Modular V10 (6.8l)  
Sponsored by:
Sponsored by:

code P0171

Reply
 
 
 
Thread Tools Search this Thread
  #1  
Old 07-05-2014, 11:41 AM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 171
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, 10:24 AM
Krewat's Avatar
Krewat Krewat is online now
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 37,433
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, 01:35 PM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 171
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, 05:53 AM
CPaulsen's Avatar
CPaulsen CPaulsen is offline
Senior User
 
Join Date: Apr 2011
Location: Southern Oregon
Posts: 399
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, 06:40 AM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 171
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, 03:37 PM
wendal wendal is offline
Senior User
Thread Starter
 
Join Date: Mar 2003
Posts: 171
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
Rough Idle and Engine Light mwoolard1912 1997 - 2003 F150 10 02-20-2017 12:21 AM
Check Engine light p0174 p0171 Benjamin Silva 1987 - 1996 F150 & Larger F-Series Trucks 1 04-30-2016 09:00 AM
intermit. rough idle, check engine w/ P0171 & P0174 codes hhoelsc 1997-2006 Expedition & Navigator 152 04-01-2016 09:26 AM
P1633,0500,0171,and 0172 acm05fsu 1997 - 2003 F150 13 12-04-2013 07:46 AM
P0171 and P0174 HELP!!!!!!!!!! Viper2 Explorer, Sport Trac, Mountaineer & Aviator 3 03-24-2005 10:10 AM


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 Off
Pingbacks are Off
Refbacks are Off

Forum Jump


All times are GMT -5. The time now is 10:24 AM.