Car stumbles around 2-3k rpm @ random..no code

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My question to the title is why? I went from constantly getting a code 34...to now just a 55 (meanking all is good) without changing anything:rolleyes:
At most just resetting the ecu trying to get rid of it after fooling around with different things. I can't figure this out. Only thing is when it sutmbles, or feels like it's gonna die..I hear what I guess is the Eccs relay click everytime the tach needle drops. I don't know if there's a loose ground or what. I definitely know it's not the battery ground cable..triple checked that. And the ground wires on the head above the exhaust manifold.

Wiggled different parts of the harnesses under the hood..nothing. Seems to only happen while I'm moving?

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Also I couldn't even get my knock sensor bolt loose...are they normally that tight? It's easier for me to turn my spark plugs than the bolt to that thing. For a sensor I wasn't expecting it to be on that tight. Was using a an extension bar with a wobble adapter and socket. Trying to go b/w the runners of the in. manifold