2010 KK po175 and cyl2 misfire

[pnassetta1968]

I have a 2010 Liberty 3.7 and I am baffled by a po175 code I am getting. I have changed plugs, injectors, map sensor. Swapped coils and code remians and all while getting misfires in cylinder 2 only. I just did a compression test

	cyl 2	cyl 4	cyl 6
dry	208	180	198
oil	235	228	225

any help or advice appreciated

 

[pnassetta1968]

2010 Jeep Liberty Limited 3.7 engine approx 180k miles

ok so no responces here to date and I am still having issues, I am convinced my randon inconsisten misfires in cyl2 have to do with my rich condition unless someone wants to lead me otherwise. I am getting consistent po175 and every now and then getting po172. Both my LTFT s are low Bank 2 -32 and bank 1 is -28. So there has to be something in common right?

Lets start back when the error codes first happened.My son who is AD in Air Force was getting misfires in cyl 2&4 so changed out his plugs coils and injectors. That seemed to solve the misfire codes he was getting but soon started the code po175. Fast forward to now, what have I done

I changed the plugand injectors again convinced it was the issue. Then I moved coils aroun. Ok back to square 1.Since I really don't know how to diagnose this issue I followed the most likely causes. Here is what have changed out in order.

Air Filter
Bank2 upstream O2 sensor
MAP Sensor
checked compression (good)
Temp Sensor
Vacuum Hoses
PCV Valve
Checked fuel pressure (good)
Air Temp sensor
Throttle body
checked cooling system pressure (good)
intake manifold and all gaskets
EGR Valve
Induction cleaned valves
Ground strap from alternator to firewall
checked all fuses and relays

I have run out of ideas and latest issue I found is that when I disconnect my battery the engine shuts off but it seteh alternator is work as I checked charging and it's 14.2 as it shoould be. if anyone else is as crazy as I am thinking how improbable my alternator is bad and causing my codes it's relatively easy swap out but honestsome direction here would ease me up a bit.

 

[DadOSix]

Let’s jump back to your plugs.

Did you use the stock NGK or something else?

Second, go over that wiring extremely carefully. This jeep is 15 years old and they are wrought with electrical gremlins. Especially the older ones - KJ;s

 

[pnassetta1968]

Let’s jump back to your plugs.

Did you use the stock NGK or something else?

Second, go over that wiring extremely carefully. This jeep is 15 years old and they are wrought with electrical gremlins. Especially the older ones - KJ;s

Yes I used NGK plugs

 

[DadOSix]

Yes I used NGK plugs

understood - then i would go thru the wiring to that bank of cylinders carefully and look for any nicks, breaks or green crusty places. You mentioned grounds up thread - did you check out those on the back of the cylinder heads as well?

 

[pnassetta1968]

understood - then i would go thru the wiring to that bank of cylinders carefully and look for any nicks, breaks or green crusty places. You mentioned grounds up thread - did you check out those on the back of the cylinder heads as well?

It is both banks though ...

 

[ikuo78]

The correction value is quite rich in fuel, so look for the sensor that is guiding that correction value.

Check whether the output and resistance of each sensor are within the specified values.

It looks like you replaced most of the relevant sensors.

There are 4 O2 sensors, so there may be something you missed.

It's not a bad idea to completely discharge the PCM, reset the learned correction value, and then see what happens.

Although it is rare, some vehicles have had their alcohol content settings changed.
You may want to check the detailed settings using an advanced scanner.

If you take your time, you will definitely find the cause.

 

[pnassetta1968]

The correction value is quite rich in fuel, so look for the sensor that is guiding that correction value.

Check whether the output and resistance of each sensor are within the specified values.

It looks like you replaced most of the relevant sensors.

There are 4 O2 sensors, so there may be something you missed.

It's not a bad idea to completely discharge the PCM, reset the learned correction value, and then see what happens.

Although it is rare, some vehicles have had their alcohol content settings changed.
You may want to check the detailed settings using an advanced scanner.

If you take your time, you will definitely find the cause.

Everytime I changed a sensor or did anywork the PCM was drained and reset