2005 E53 4.4i N62 Misfire Help!

[kamhoe]

I need some advice or guide to troubleshoot the misfire that never go away!

The service light recently pop up and I did the code scan and found

VIN: ...LV13586
Mileage: ~69250
Symptom: Engine keeps shaking; losing power; service light blinking on starting and stay on

2019-02-23
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0304: Cylinder 4 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected
P0308: Cylinder 8 Misfire Detected


I replaced 8x NGK BKR6EQUP spark plugs and did a few new scan on different dates and found


2019-03-02
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0305: Cylinder 5 Misfire Detected
P0306: Cylinder 6 Misfire Detected


2019-03-09
Current Fault Log
------------------
ECU reports no current faults

Pending Fault Log
------------------
P0305: Cylinder 5 Misfire Detected


2019-03-10
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0302: Cylinder 2 Misfire Detected
P0305: Cylinder 5 Misfire Detected


So I decided to replace 8x Bosch 0 221 504 464 coils and did new scan and found

2019-03-17
Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected

Pending Fault Log
------------------
P0301: Cylinder 1 Misfire Detected
P0304: Cylinder 4 Misfire Detected
P0305: Cylinder 5 Misfire Detected


I am thinking of the fuel injectors that cause the misfire and I found the guide on

https://www.pelicanparts.com/techart...eplacement.htm

I am wondering if this is the correct guide for my N62 engine?


I never deal with fuel injectors before and I curious if this not too tough can be done by myself in my yard?


I have some experiences for battery, spark plugs, ignition coils, window regulator replacement & dashcam hardwiring.


I welcome anyone's advice and info to fix the problem!