How many O2 sensors on a 2002 Explorer XLT?

[Bobalouie76]

Hi all,
I need to replace the Y pipe (Cats) on my 4.0 V6 2002 Explorer and might as well replace the O2 sensors while Im at it. I cant seem to find any info on hoe many O2 sensors there are. I have found answers online stating there are 3 and answers stating there are 4... soooo what do you all say? I know I will get the right answer here.
Thanks,
Matt

 

[kryhavoc]

its usually 4 sensors on the 2wd models. that cat pipe is 400$ on rockauto.... expensive to replace.