Knocking after pull- went away?

Connormcclark

New Member
Oct 6, 2025
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Chico
I was driving my (1997 GT) 4.6, down the road very soon after doing an oil change, I’m sure everything was tightened down correctly oil filter was replaced too, and no oil has leaked, it was also 5w20 Mobil 1 oil. After doing a pull to about 5k rpm, my engine starts knocking and stalls out, I start it again read the codes and there are 4 different misfires, cylinder 1,4,6 and I think 5, and some smog thing too, then I clear them and restart it, it struggles for a bit and then the knock goes away completely, and I drive home. The next time I start it it’s running beautifully again, and after a while it seems a little off, and the code is saying only one cylinder is misfiring. Not sure at all what this could be, I thought I blew my motor and then it fixed itself. No smoke out of the exhaust or oil leaking at all, coils are all still attatched well, alternator replaced recently. Engine is tuned by previous owner pretty sure. Any help is greatly appreciated!
 
Maybe a slightly loose connector/connection that the high revs jiggled loose but now its sort of making connection? Swap the coil on the bad cylinder with another cylinder and see if the code follows the coil to the new cylinder.
 
Address and eliminate the misfires.

There is zero reason to do anything else until that is permanently resolved.

The "knocking" that you heard is very likely cylinder detonation. It only takes a few of those to grenade the whole engine.
 
Address and eliminate the misfires.

There is zero reason to do anything else until that is permanently resolved.

The "knocking" that you heard is very likely cylinder detonation. It only takes a few of those to grenade the whole engine.
The misfires are all gone now, it’s running fine, idk what it could have been. Just trying to make sure it doesn’t happen again