I just need to know if a bad O2 would cause a skip when the truck is going up a hill? The code reads that it is an O2 sensor which I'm going to replace in about a week. on level ground its fine or when the truck is still cold. by the way it is a 5.4L

Thanks
Jeff

 

What is the exact code? Your O2 may be just fine. Post the exact "P" number, please.

 

I think it was P12

 

I think not. It will have four numbers past the P. Most likely causes of your "skip" is a cylinder misfire either fuel or spark related. If one o2 were bad then that half of the engine would either be rich or lean all the time. Still need to know the exact code retrieved from the CEL.

 

I had the guys at Advanced Auto Parts hook up the reader to the truck and it read that it was an O2 he said which one but I can't remember right now, and also a #8 misfire.
They said to try the O2 first and if that didn't help the skip than replace the coil mod. If I have to do that I'll do the plugs as well.

 

Just remember that parts stores that have free scanning are always going to try to sell something according to the code they read. They are not "diagnosing" your problem, just retrieving a code and selling parts. The codes are stepping stones to a causal part. Just because there is a code that involves an o2 sensor does not mean that the o2 is faulty. I can't tell you how many vehicles come into my dealership after a venture to Auto Zone because the CEL is still on and they have a new EGR valve, a new DPFE sensor, but the P0401 no egr flow code is still there, only to find that the egr ports are clogged behind the throttlebody. Then they get mad at us for "ripping them off". Just tread lightly. I would go after the #8 cylinder misfire to begin with. Most likely a COP problem, but check the plug also.

 

Wrong on their part.

Fix misfire first. Maybe even swap in 7 other new coils or you will be doing this drill over and over again.

THAT might be causing the O2 sensor reading that is tripping the CEL.