I was driving tonight (new 22RE longblock, Approx 350 miles on it) and the check engine light came on. The truck was running fine and all gauges were reading normal so I continued on my next 8 miles to get home. I did the trouble code thing and got code 21 (O2 sensor). This was the one I was hoping for as I have a new Denso O2 sensor in the box that I was going to put on soon. I was waiting to put the new O2 sensor on in a week or two as I was thinking about swapping out the catalytic converter at the same time (186K miles and it looks original). My question is since the truck is running like normal will an O2 sensor leave me stranded? I can get a new CAT (probably 2-3 days as I have to order one)? Does it make sense to go ahead and put the O2 sensor on now or wait a few days (Saturday) until I can put a new CAT on at the same time?

 

an O2 sensor wont leave you stranded, I drove around for a week without it

 

FYI,
I have also seen a few times where the 02 code doesnt mean the O2 sensor is necessarily bad.

 

Since I had the new O2 sensor I just went ahaed and swaped it out this morning and cleared the code. I went on a short test drive and everything seemed good and the check engine light did not come back on. Hopefully this will be the end of it but this truck is always coming up with something new for me to fix.