Topic Sponsor
2004 - 2008 Ford F150 General discussion on the 2004 - 2008 Ford F150 truck.

Help understanding O2 readings

 
Old 01-27-2017, 09:25 AM
  #1  
Junior Member
Thread Starter
 
Join Date: Aug 2015
Posts: 19
Liked 0 Times in 0 Posts
Default Help understanding O2 readings

I have a 2005 F150 Lariat 4x4 with the 5.4L and I had a problem with one of my coils and was able to get that fixed. I do not know how long it was not functioning but it was a while I am sure. With that said, I question my catalytic converters due to low fuel efficiency and the O2 sensor readings.
The front sensors seem to be functioning normally and respond to changing conditions well. The rear ones both fluctuate quite a bit though. I am of the understanding that they should be pretty steady for voltage and not jumping between .08v and .7v. Would this make the cats suspect? I have also included a screen shot of the readings.
Attached Thumbnails Help understanding O2 readings-img_3075.png  
daveborg98 is offline  
Old 01-27-2017, 09:28 AM
  #2  
Moderator
 
BadFish523's Avatar
 
Join Date: Mar 2015
Location: Arlen, Texas
Posts: 5,712
Liked 666 Times in 556 Posts
Default

Did you disconnect the battery when you worked on your coils? Did you do the relearn after? I ask because Im still struggling with a low MPG after doing coil work and the relearn.
BadFish523 is offline  
Old 01-27-2017, 09:31 AM
  #3  
Junior Member
Thread Starter
 
Join Date: Aug 2015
Posts: 19
Liked 0 Times in 0 Posts
Default

I did not do that. It started raining and I completely forgot in the scramble to get it done. We are moving so I had to borrow a driveway and tools.
daveborg98 is offline  
Old 01-27-2017, 09:42 AM
  #4  
Moderator
 
BadFish523's Avatar
 
Join Date: Mar 2015
Location: Arlen, Texas
Posts: 5,712
Liked 666 Times in 556 Posts
Default

A relearn may help you. That will make the system relearn fuel efficiency with the new parts.
BadFish523 is offline  

Thread Tools
Search this Thread

Contact Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: