04 trailblazer lt 4.2 2wd PLEASE HELP P0016

04tblt

Original poster
Member
Dec 6, 2021
4
Alabama
I recently acquired two more trailblazers and one running and driving just been sat up for I would say 2015 from last inspection in Mississippi. It has a gutted cat already probably from the code but it misfired on the way home and when I got home I hooked my scanner up it was random multiple misfire I replaced the plugs it hasn’t done it since but it still has p0016 code and engine idles a little rough. Any advice it greatly appreciated!
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Have you tried a search? These threads have a lot of info:

 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
Where and how was this sludge found?

You could try a flush however it carries its own risk of dislodging said sludge and clogging oil passages to vital parts like bearings. I would then do an oil change with a cheap oil and filter, run it a while (not driving), drain and refill again with the good stuff. This would hopefully mitigate the possibility of causing more damage. I would also replace one quart of oil with DexVI transmission fluid for a long term cleaning.

Then, replace the CPAS. This will also show how much sludge has clogged it. If these things still don't fix the code, I would look into replacing the camshaft phaser gear if the oil is staying relatively clear. If not, I would replace the oil again.
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
With that much sludge, it was either a very short drive car, or a bad thermostat-hence the gutted cat.
Too bad it can't be internally steam cleaned in the car, cause that's what will do the trick.
 

04tblt

Original poster
Member
Dec 6, 2021
4
Alabama
Ahh kinda a backyard mechanic do my own work kinda guy. So far 2 500 mile oil changes since I’ve had it and both times it’s been black . I’ve ran some seafoam and transmission fluid the first time about a quart of them mixed so half and half and 6 quarts synthetic 5w30. Right now it has about 300-400ish miles on this change and when I first got the truck it has about 2mpg all around now I say maybe 6mpg it’s slowly improving and getting better power but the sludge is still pretty thick from what I can see in the fill cap.
 
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