Engine knock / valve rattle hot or cold

[Tod Geddes]

Have a 2005 GMC Sierra with 5.3L engine and about 130K on it.  Have been getting a rattle when accelerating or under load.  Check the OBD II  but no errors showing.  Have run fuel cleaners and such, not  much better.  Oil and filter changes did nothing and neither did different grades of gas.   Had the anti-knock sensors replaced back in 2020 after OBD error,  along with spark plugs and wires

Any suggestions?

[richard wysong]

check the egr system. it should have set a code if malfunctioning but you may have Gremlins

[CamGTP]

Can it be heard on video?

[dna9656]

D_ _ _ GREMLINS!
I have heard that when replacing engine sensors the OEM wire harness and the connectors there on don't perform well after the have been disturbed (disconnected and re connected to the new sensors. I have also read that any/all other than GM harnesses are not reliable.