96 f150 was a 302 now it has a 351w. The bank 2 o2 sensor heater will only warm up after I drive the truck and cools down when it idles and stops working. Bank 1 works fine. I replaced bank 2 with 2 brand new Bosch sensors and repaired a broken wire that I had previously tapped into to run a stupid narrow band air/fuel gauge. It keeps tripping cel codes 153, 155 and 1151. I really need this fixed it has to pass inspection it's already 4 months late lol. Plus it never goes into closed loop mode and mpgs are poor.

 

I am sure you have tested the rest of the wiring for the heater ckt . You have , haven't you ? If 2 new sensors , likely a wiring issue . Of course , ck all fuses .

 

How do I go about testing the harness? I looked it up put couldn't find any info. I have a multimeter and a power probe tool.

 

you may have to buy a diagram . I have a power probe , and power probe Hook ! You need proper information before you jump . Tools do no good without the proper information .