7.3 tapping

[jharms]

Help, I am new to this site. I have a 2002 F250 7.3 that I just bought with 60000 miles on it. The problem is the engine makes a tapping noise at idle. I had a mechanic isolate it to the #8 injector. when he shut it down the noise went away. They put in a new injector and the noise was still there. Could it be fuel pressure? Any help would be greatly appreciated. The mechanic did not know what to do as he was not an expert on diesels.