Engine rough idle. code p1131. replaced o2 sensor.

You don't clean O2 sensors , if bad you replace them . An only if there is a DTC - diagnostic trouble code or you check out O2 sensor performance with testing , using scan tool , lab scope or multimeter . A rough idle is usaully caused by a vacuum leak , a engine misfire , IAC - idle air control air passages clogged . There are videos on youtube on how to test to find rough running problems .

O2 sensor po136,front and back sensor to be replace.

What make vehicle do you have ? This code doesn't necessarily mean the sensor is bad ! That is why these thing's need to be tested before replacing , check with a scan tool that shows engine data . This code indicates a lean condition ( vacuum leak ) or a ( fuel problem ) P1131 Lack Of HO2S Switch Sensor Indicates Lean Fixed Lean O2 Is the sensor lying

Check the help link provided below:----

Ford runs lean and idles rough?
http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Thanks.

P1131 Lack of HO2S-11 Switch ,Sensor Lean
P1151-Lack of HO2S-21 Switch ,Sensor Lean
PO171- System to Lean (Bank 1)
PO174-Systen to Lean (Bank 2)

Fuel Filter -Plugged
Low Fuel Pressure
Evap System -Leaks
Leaks - in ducting,air filter to throttle
PCV -Leaks
Exhaust System -Leaks
O2 Sensors-worn out

The P1131 means that your upstream oxygen sensor (the one closest to the engine) is not switching rich to lean and back as frequently as it should. This could be due to a vacuum leak, a failing oxygen sensor, or a rich fuel mixture.
Rich mixture - Too much fuel, not enough air.
Lean mixture - Too much air not enough fuel.

Your auto has four O2 sensors. Two upstream and two downstream; With two banks. Bank 1, sensor 1...and bank 2, sensor 1 are the two upstream (exhaust manifold before the catalytic). Bank 1, sensor 2 and bank 2, sensor 2 (other side of catalytic)

Code 1131= upstream; bank 1..sensor 1
Code 1151= upstream; bank 2..sensor 1
Code P0136 (generic code) bank 1..sensor 2 (questionable)

I wouldn't spend the money to purchase 3 sensors. Highly unlikely all three are bad; Cost is about $40/ ea.
Since there isn't a code for the cat's themselves, I would suspect the O2 circuit is malfunctioning. The rough idle is another clue.


Take an ohmmeter set it on X10 scale and measure the resistance from engine to body and body to negative post on battery terminal. You should read zero ohms (full needle deflection). If you do go buy two upstream O2 sensors. If you read
open or a high resistance run two straps from eng. to body...and body to neg.batt. post.

FixYaWIZ................saailer



I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

p1131 code is a o2 sensor

po301 thru po306 all misfire codes cylinder 1-6 remove plugs and replace them..... set the plug gap first
i suggest u replace the wires also if they never been replaced all these misfire codes can set the others and one is for the oxygen sensor ( 02s or HO2S) CIRCUT MALFUNCTION do u know how to check wireing systems
do the tune up plugs (set gap) .052-.056 change the fuel filter also. clear the codes hows it run
this info is for 98 E-250 4.2Litre
what engine do u have 4.2L or 4.6L i know it is a v-6 by the codes

P1131, Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1 ...

MOST LIKELY THE UPSTREAM (BEFORE THE CATALYTIC CONVERTOR) O2 SENSOR IN BANK ONE IS DEFECTIVE, ALSO CHECK FOR ANY ENGINE VACUUM LEAKS, A CAN OF CARB SPRAY HELPS TO SHOW IF ANY LEAKS ARE PRESENT, THE IDLE RPM WILL INCREASE WHEN THE CARB SPRAY HITS A LEAK, IF NO LEAKS FOUND REPLACE THE BANK ONE O2 SENSOR.