P0302 cylinder misfire code keeps reappearing

[B-lake]

Over the last 4 months been getting P0302 with P0175 codes.
Infiniti said Catalytic Converters needed to be replaced. Replaced Catalytic converters in December 2019. Alarms still came in about 2 days after.
Our local Nissan diagnostic suggested fuel injectors needed cleaning. That was done Jan. 2020. Alarm came back in and they re-diagnosed it saying we had an exhaust leak. That was fixed Jan. 2020.
Also in Jan 2020 - Ignition coils replaced, all new spark plugs.
PCV valve and MAF sensor both replaced in Feb 2020. Here are the images in idle and running at a steady 1500 rpms. Maybe some can see something not normal and fill me in. Tired of tossing money to diagnose it every few weeks. I put the files in Google drive to make it easier. Thanks

Infiniti - Google Drive

drive.google.com

 

[marctronixx]

what model is your car?

didnt look at your attachment. what codes are you stuck with now?

 

[B-lake]

P0302

 

[marctronixx]

what model is your car? and do you no longer get the P0175 code?

depending on your car year, did you get manufacturer recommended plugs ?

did you check the compression values in the cylinders? are the up to spec?
you could have a leaky valve cover and oil could be getting into a plug cylinder causing a misfire.

if you have an older model car, you may have a failing petrol pump...

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[B-lake]

2012 infiniti qx56

P0175 comes and goes stays as pending on my reader.

Code that comes in permanent is p0302.

Took it to infinti yesterday they called back and said they believe its cylinder 2 spark plug with a cost of $435 for it. I told them they were just replaced and that these issues were there before spark plugs replacement.

Would a spark plug cause fuel trim to be rich?

They replaced o2 sensors with 2 NTK exact fit 24449 and bosch a 1 exact fit 17006

 

[marctronixx]

as i mentioned you should check compression and leaks as you may have an oil leak.

did you get the recall done? if so, there could be some issues from that also.

 

[primov8]

100% agree with marctronixx as those steps should have been done when checking for this DTC. A P0302 is related to a misfiring #2 injector. I don’t know what these techs are doing, or more so not doing. The intake manifold has to be pulled off in order to physically check the injector(s). Not only for carbon buildup or blockage on the ends of the injectors but also checking the ohms of the injector(s) to confirm it is within operating specs. Also to check the pigtails/harness for any exposed wires. I hate to say it but whomever the techs were at Nissan/Infiniti you dealt with, is just guessing on the fixes, hence the failed results.