My 1992 Bronco 5.0 has a faint knock when cold , but it gets worse

yes, i agree

It's no spring chicken-it's twenty years old.Sounds like the crankshaft and/or connecting rod bearings are shot.Time for an overhaul or another motor.If the car has not seen regular oil changes,this could be accelerated wear due to a clogged screen on the oil pump. Someone could hook up a gauge to the motor and determine if oil pressure is adequate. (We had a T-Bird with 5.0 that had this same condition-it will only get louder,and eventually blow up)

i had a 1995 cougar that did the same thing..but only when idled over 2 grand...and i that was due to a spun bearing..if you mud the truck that could be the issue..