egr valve
 

So, I decided that I would replace the egr valve on my 92 accord LX sedan 2.2. In doing so i broke the stud that holds the nut when you tighten it. The other stud is fine, but now when I give it gas(while driving) it makes a tapping noise. I was told that the noise is because there is air getting into the valve. MY question is: can that stud be replaced and if so how or how to stop the tapping noise.

1992 Accord LX sedan
automatic
152,000 miles