Need help figuring out my knock problem...

I need any and all help figuring out where I could be getting knock from.

The header was rubbing on the frame - Dustin thought that might be the issue. Got the pipe heated and moved away and it still shows knock.

Replaced both front O2 sensors, so they're new.

Sprayed carb cleaner around where the EGR crap (it's been removed and plugged) hooks up and no leaks there.

The knock sensors only have about 15,000 miles, so I doubt they're bad.

Any other causes you guys can think of? This is driving me insane.

Is it audible or just detectable?

Just detectable as far as I know. The knock appears sporadically. Everything looks fine in HP Tuners, then it'll show knock, then it goes away. A few seconds later (20-30?) it comes back for a second, then goes away...

This was posted on PT:

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Originally Posted by OnyxSilveradoSS

has the sensitivity been changed in your tune for the upgraded springs? My 918's were making so much noise it came up as some false knock.

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And another post...anyone familiar with this:

Quote:

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Originally Posted by fossil

Go into your HP Tuners and you can adjust the frequency numbers of the knock sensors, so your pcm will not pick them up. Make sure it is not a true engine concern first.

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He may just need to desensitize the knock sensors

aftermarket rockers might be making some noise if you have them.


Also shortly after i installed my 05+ efans and bigger rad and washed down the engine at the same time, i noticed that i was gettin alot of audible knock all of a sudden, i ran some seafoam thru the vac line, and in the tank and higher octane fuel with no differance. Then i got a CEL light and a knock sensor code, turns out there is a problem with water getting into the sensors and corroding the wiring, so i bought 2 new sensors and a new harness and need to get it installed.

This could be your cause, just thought id throw it out there.

Yeah I had the same issue with my Z71's knock sensors. But these are such low mileage, I have a hard time believing it's them.

But I do have the PRC dual springs so maybe that's the problem.