2001 F150 4.6. Just replaced all 4 oxygen sensors and spark plugs. Replaced rubber grommet on brake booster as it was leaking vacuum.
Truck is still running rough hesitating.
Pulled codes came up as PO141 oxygen sensor heater circuit. PO171 passenger side cylinders running lean. Fuel trim outside limits.

 

Have you checked for vacuum leaks at the intake and pcv ? Did you re set KAM after your repairs ? Just a couple of thoughts ...

 

KAM ?
Couldn 't see any obvious vacuum leaks. Codes are new, problem isn't. Truck has had a hesitation or hitch for years. Truck has about 70k miles on it.

 

KAM = keep alive memory . After repairing fuel trim issues , you need to re set it . If you do not have a scan tool that can re set it ,Disconnect the negative battery cable for 5 min. then reconnect it . Do you have a scan tool with live data ? You can graph your short term fuel trims while spraying carb cleaner to find vacuum leaks . You can also graph your o2 sensors to see what is going on . Fuel trims long / short should be + - 5 % . anything over or under is an issue .

 

If you would look closer at the 141 code description it tells you the circuit to that sensor is 'open' on bank 1 sensor 2, the cat monitor sensor.
So it's not the sensor/s.
The 176 code is the upstream sensor for the 'same' bank.
Look at the harness for opens or rub-throughs or burns to ground.
This is why your replacements made no difference.
Fix this first then address any other issue there may be.
Good luck.

 

Thanks bluegrass.

 

Any one place in particular I should look for bad wires? Passenger side oxygen sensors.

 

P0141 is an electrical " heater " code . P0171 is a lean code .

 

Is there a way I can check the harness using a DOVM. Bank one sensor two shows twice the resistance on scan tool as other sensors.

 

Does anyone have a copy of the wiring diagram?
I have a complete harness from a 2000 5.4, anyone know of they are interchangeable?