4.3

[4.3 Bangin silverado]

I have a 2003 chevy silverado 4.3. and i was doing about 60mph and i started to hear a ticking noise to i sped up and it was still there. i started to slow down and it sounded like it was slowing down. Any ideas what it could be? And my oil pressure gauge doesn't seem to be working bc it when i stop at a red light it'll drop to 0 then it slowly moves back up and while i'm driving it'll move up and down. Any help would be appreciated

[O_J_Simpson]

Sounds like metal migration.