PCM sends reference signal to the sensor. *should* be 5 volts. Or very close. See what the scanner thinks that voltage is...... although, if the PCM was actually SEEING a low voltage going TO the sensor, you would think it would whine about it.

Wonder if an intake gasket didn't slip on installation...... Might wanna check crank case for vacuum..... Disable PCV system, plug up the hoses, take off the oil cap, and let the engine idle. You *should* feel a slight breeze out the oil fill hole.

 

If it was an intake gasket, I feel I should of had this problem a while ago right? I did that a year ago maybe. Just an update. I know the pcv valve is okay. Just checked. Can check the 02 sensor voltage with a meter at the moment. But I pulled the PCV valve and it smelled like fuel. There has to be fuel in my oil now. On start up this morning almost sounded like a backfire. Weird because the truck runs fine. And my ST fuel trim now this morning is showing -10. As it warmed up the ST moved back close to 0 and into lean numbers again and back into rich numbers. Not steady but I know ST isn’t always steady. LT is still showing lean with 24.8 now. 02 was switching nicely on first start up with rich and lean. Coolant sensor reads okay on the scanner. Spark advance at idle is about 20 degrees. The LT is no longer at 32. Which is nice. But still. 21-24 for LT is still a bit excessive in my opinion.IAT is also doing its job. Just not sure what I’m missing.

 

02 sensor has a good 5 volt refrence

 

What's you oil smell like? Probably a fair bit of gas in there too......

 

Yeah I posted above this post with more details. Oil does smell like fuel.

 

Hhhmmmmm...... Change the oil, and leave the battery disconnected while you do it. (resets the PCM) Might want to consider a leakdown test as well..... See what it looks like.

 

****UPDATE****

My headers were the issues. Had a lot of cracks and etc. couldn’t hear an exhaust leak but hey that was the issue with my fuel trim. LT went from 30 to 8 after replacement with stock manifolds. 8 is a bit higher than normal sure but not worried right now. It should still let the catalyst monitor complete so I can pass emissions!