f150 making noise
 

its a 2004 f150, now sometimes whn i try to start the truck, it makes a loud screeching grinding noise, and then ill have to try and start it again usually it starts the second or third time, but my main issue is this, any time i accelerate it SOUNDS like its and exhaust leak, but the exhaust and muffler are both in perfect condition, when i tried to trade it in the other day for a new car, the appraiser said something along the lines of a rod was missing from the engine, any idea what this could be???? and any idea how much it would be to repair it?!

May be timing components