2001 Jeep Grand Cherokee Laredo 4.0 will not stay running

Okay so here it goes I have a 2001 Jeep
Grand Cherokee Laredo 4.0 four-wheel drive
it had OBD trouble codes for crankshaft
position sensor camshaft position sensor
and both were replaced then also spark
plugs coil pack O2 sensors and it was still
running rough and die at anytime now
what's going on is I was told to replace all
that and I did now I sent it to a shop and
they went through it said there was some
wiring that was bear and they fixed it will
come to find out it didn't fix it so then they
tell me that it's the ECM so guess what I do I
replace the ECM now with the placement of
the ECM it's still wants to die out and run
rough so my question is what is causing this
to run rough and still after everything I've
already replaced because the shop told me
to come pick up the vehicle because they
could not do anything with it no more but
presume to tell me that my wiring harness
from the ECM to the injectors and to the
sensors was the problem and needed to be
replaced now before I replace this wiring
harness is that what needs to be done to fix
the problem because I am at wit's end right
now and I need to know what I need to do to
fix it so if anybody has any info and what
needs to be done or what I need to buy
please let me know ASAP thank