I have a 2001 F-150 4.6L 2wd, when I am driving between 40-50 miles per hour there starts a banging coming from the engine, I don't know what it is exactly but I'm under the impression that it is the timing chain I was wondering if any body had any other ideas.

 

i have a 01 f150 with the 4.2L 2wd, and when i am at 40,50, or 60 mph and 1500 rpms it starts pullin and feels like the engine wants to drop out of the engine bay. like im hitting alot of bolders.. maybe this is the same as the bog dans?

 

check for a heater hose coming from the engine to the heater core. There is a plastic valve which should be close to the engine. Sometimes this valve moves from it's factory location and starts to move its way to the heater hose. this valve can actually bang against the heater hose connection creating a loud banging noise. check that and let me know.