97 ford f150 4.6.keep getting 141 and 136 codes.I checked red wire on 02 sensor and volts are staying around 13 volts it is an after market o2.someone said it will not work on ford.Hate to go buy another on because that one is new.Is there anything else that would cause 02 not to switch.its bank 1 no 2 sensor

 

What this would require is to either start at the PCM or the O2 sensor and measure the millivolt changes. A scan tool is the better method to do this because no connections need to be opened up to get the info. What kind of test equip do you have to use?
You are probably measuring the heater voltage circuit.

 

i have an inovia 3140b scanner but don't know how to use it other than getting codes.i can go to live data but don't know what im looking for w let me know what to look for and i can mess with it

 

Do you have the instruction manual?

 

no it didnt come with one gives web site for inst

 

The only thing I can suggest at this time is , get the engine at operating temp and post the data it gives. We will all take a look at that data and see what we come up with.
It is easier to examine if typed in a line going down as you see it on the screen.

 

p0136 calc load 95.3 ect(c) 93 stftb1(%) 25.0 lift b1 -14.1 stft b2 21.9 lift b2 18.8 eng rpm 1760 veh speed 47 sorry i couldnt list then over each other but i don't know how

 

Just to make sure I understand your numbers, Long term Fuel trim bank 1 ,is that a minus sign or just a dash by you?

 

Is there a possibility that you have the O2 sensor plugs crossed? The readings seem to indicate that because Fords use what we call rear fuel trim.

 

sorr it took so long to get back,had to go out of town unexpectantly.Theres a possibility wires could be crossed on plug.Someone put a new plug on it do u know what the 4 wires should b reading coming from box to o2.went to ford place and got right o2 sensor but still reading 141 heater circuit.switched white wires thinking that they could have been switched but got same results.Do u know which 02 wires go to wires on harness have 2 white,black,and gray.will have to get under it to see what color wires are going to box