I have an 02 dakota with the 3.9L. I originally was getting all 8 codes for 02 sensors and went ahead and replaced all 4 with bosch direct fit oe sensors. Still getting codes for the 02 sensors but now they vary, sometimes I get a 136 other times I will get 31 and 51 it varies. if I drive on the hwy for a while and check the codes I will get all 8 codes again.. Please help as I am at my wits end with this since these sensors were not cheap and was a pain to replace...thanks

 

Welcome to the site. I will move this thread to the second generation Dakota section,
FF

 

after you replaced the o2 sensors did you reset the computer ? not doubting youre work just something else that i know I have looked over before .

 

I reset the computer through my OBD2 scanner and as soon as restart the truck the check engine symbol pops back up with o2 sensors codes.