95 z71, dies in idle, at stops, rattles under load, pings after shutdown.

Recently got my father in laws old truck. Ran fine
but was due for plugs, wires, etc.  I changed the
wires and it began wanting to die while idling,  
when put into gear, when pulling up to a stop, etc.
Also developed what sounds like a rattling, when
under load, but only after load release. If you kick it
into OD, no rattle until it upshifts again. I did notice
when i pulled the old plugs that it had bosch
double platinum plugs. I replaced them with
delcos. Since then, i have replaced a cracked
manifold, plugs again,  wires,  rotor, and cap.  All of
the above electrical components were pretty burnt,
and when the truck is running correctly it runs
better than before. Just can't figure out the issue.
Im leaning towards maf sensor, or fuel pump.  Any
advice or thoughts is appreciated.