Ok, I've been searching and have found no clearcut answer, how many o2 sensors are on these 4.0 motor? I'm guessing 3, would that be correct? I have a code P133 that says the Bank 1, sensor 1 is bad so I figured if I am changing 1 I will change all since they are almost 16 years old and by what I find on Rockauto, there is 3 sensors so I ordered the 3 listed that are Bosch units. Any other tips for changing these out? Thanks in advance for any help.

 

A 4.0 Ranger has 1, 3 or 4 oxygen sensors. It depends on the year.

 

My truck is a 98 model year that was produced as one of the first and I believe it was built in like September of 97. I have found some things that were 97 model year on the motor. Thanks for the reply, I ordered 3 from Rockauto yesterday after seeing that it was indicating 3 and possible 4 with the 4th being after the cat. I figure the truck is nearly 16 years old and if one is failing then the others are probable getting soft as well. I know I wouldn't change only 1 bad spark plug so that is why I ordered all 3 and they are Bosch units which should be good. I just hope I can get things out, I have the appropriate o2 socket just hope theres room to get to them.

 

95~2003 Ranger 4.0L have 3 O2 sensors. There is 1 sensor for each of the 2 cylinder banks and these are upstream of all cats. The third one is for cat efficiency monitoring and it is positioned after one or more main cats.