The famous P03XX strikes again.

BUT

1 - Not the coils. (Already changed and it persisted)
2 - Not spark plugs. (Also changed, persisted.)

Important information:

This only happens after a while. Car starts fine and runs fine, idles fine and accelerates for a period of time. But after X amount of time minutes-wise it starts misfiring and running bad, after it gets "hot" (?) And it is only on cylinder 3.
I have had cilynder 2 misfire with this same car in the past with the exact same issue (going bad after an amount of time) but in that case was the coil, which was changed and solved, and now it is not, as said above.
Which other options we have left? (Aside from spark plugs, injectors or pump) like leaks or hoses or something.

Thank you all in advance!

 

Kind of a long shot but possibly check the large blue 6 pin connector for the 1,3 & 5 coil pack sub harness that is clipped to the passenger valvecover. Mine was loose one time and caused a random cylinder misfire but something like corrosion or a burnt pin could cause a single cylinder misfire on one of the passenger side cylinders.

 

Thank you.
That's a possibility, but not the case in this scenario.
Checked the plug connector and seems fine
Any other ideas?