Thanks to those who helped before with my PCV tubing replacement on my 99 Expy 5.4. See previous thread if you're interested. https://www.ford-trucks.com/forums/8...-dead-rig.html

So, I finally got the tubing and valve replaced, but had to remove or loosen just about everything around the throttle body. It started right up the night I got it fixed. The next night, I took it for about a 10-15 minute test drive to see if the CEL returned, it didn't. Thought I was out of the woods.

Next morning on way to work, 3 minutes in, CEL back on. Code is P1131.

Suggestions? Anything I may have done wrong in replacing the PCV tubing? Need to replace the O2 sensor? Front or back? Driver or passenger? Clean the MAF sensor? Misfire? New plugs? So many options....

Thanks.

- Solley

 

See if this helps. TSB 01-9-7 HO2S Service Tips

 

Sorry for the delay, but this late post may help someone down the road...

It was the O2 sensor, passenger side in front of the cat converter. Bought the part for around $50, tried to install but I suck and you need a special tool, so I took it to a random shop and they installed for $75.