yes unfortunately I have more questions... on the 02 explorer sport... my check engine light came on... was told o2 sensor may be out but was told there was 4 of them on my vehicle. I found 2 of them but cant find other 2... is it normal for a vehicle to have 4 o2 sensors... thank you for any info...

 

Hi,yes it is normal to have 4 O2 sensors. Two heated oxygen sensors and two monitor. There is one before, called the upstream, and one after the catalyst, called the downstream. On your specific truck, if I remember well you have three. One because each catalyst on each side of the engine (this part is called a Y-pipe. After the y-pipe there is twoin-line catalysts and there is one monitor between these two.
But, before replacing part for no reason, I suggest that you have, at least, your code scanned if you don't want to pay for the whole diagnoctic. The we will be able to pinpoint your problem.

Nic