On engines with high mileage that are starting to use oil, the oil causes a carbon buildup to occur at an accelerated rate. Any advice is welcome. Somehow, do whatever it takes get the piece out. Try long needle nose pliers or some kind of a flexible grabbing tool. If worse comes to worse, disassemble the engine, removing the intake manifold to get the piece of metal out.
Truck runs good but exhaust manifold turns beet red after running a while.
Check fuel mixture, it may be incorrect. Also, check ignition timing.