4.8is engine sludge, rough idle etc

[four.8is]

As the title says, as soon as cold weather hit the northwest , Ive started experiencing a rough idle that was not present until now.
I’ve had the car die at a light this past summer in 114 degrees , hooked up the computer and it was a bad MAF. Worked well after I changed that.
Also changed the CCV membranes, they were good no cracks etc, changed them 50k miles ago but did notice this sludge in the engine, is this normal? (See picture)

I’ve ran 3 or 4 injector cleaner bottles for the past couple months, and that was the only thing I did out of the ordinary.
No codes, no lights etc.
how can I get to the bottom of this?
I have DIS/INPA . Any tests I can do there?
Car has 154k miles

I do have a coolant leak that has developed in the last 3-4 days , very slow leak but planning to take the shield off and trace it .

What would you guys do?