u/Bekaws6425

Just replaced the coils and plugs and after all was done putting the cover back on I guess I stripped the nut on this stud or maybe even the stud looking at the pictures I took before I put it back on i didn’t realize how rusty it was

The nut is just spinning freely and all I use is hand tools can’t seem to get it off what part is that stud ? and how do you change it if and when I get the cover back off