As the title says. I have had a knock on start up but goes away instantly. Now it's more of a tick, but still a knock I guess? I have great oil pressure even at operating temperature, doesn't over heat at all. Seems as it warms up, I have a great loss of power. No SES light, no backfire, misfire, stumble, hesitation, nothing. Just feels like I'm running on half a engine.

Here's a video of the noise. A friend of mine noted how the knock actually goes away at the very end of the video, in a sense intermittent.

 

with a pipe held to your ear you may be able locate the noise more accurately.

 

Check your tq converter bolts and your crank to flexplate bolts 1st.
Also check 4 a broken flexplate. You will have to remove the trans for the best view.

 

I should mention, this is not external related. All surrounding possible areas have been checked and double checked. Not exhaust or anything like that. It's definitely internal but just not sure what.

 

So you checked everything I said??

 

The TC to flexlate is nice and tight, just how I like my women.

The flexplate to crank bolts I have not checked. My symptoms really don't point me in that direction to be honest.

For example, when I do a oil change, the knock is prolonged UNTIL oil pressure is built up, few seconds, then it quiets down to the point you can barely hear it.

 

 

That would kinda be normal for a oilchange if you don't fill the new filter b4 you put it on.
The vid you made, was it warmed up or a fresh oil change??

 

Kinda late here. But this video was right around operating temps. Car had been running for some time.

Nearly 2 months later and still ticking.

 

I would think maybe the knock sensor is getting set of and retarding the timing. A significant knock should vibrated the sensor enough to set it off.