Vacuum Leak Possible?

[arrowshooter]

Got to thinking about some things while my truck is down with a bad fuel pump. One of those things is a pesky "ping" I have had since I replaced my intake gaskets. In the hills it gets real bad until the knock sensor takes over. I doubt that it is the timing because I made sure the distributor went back in lined up with the 3 marks I made. But I do have an oil leak in the back because I did a p--- poor job with the back bead of silicon. Judging by what my idle does when I take off the oil filler cap, could this be leaking enough vacuum to cause a ping?

[billyrb]

ping would be from vac or timing being off