1995 F150 electrical issue?

My mechanic is at a loss and I'm not ready to give up yet. I drove my pickup on one day and
it ran perfectly fine, filled it up with gas at Costco and got the car wash. Drove about 40 miles
total. The next day the truck started up but was acting like it wanted to choke out and die.
Gave it gas but it had no power when I put it into drive. It vibrated a lot and seemed like it
wanted to stall out. I was able to drive it to the mechanic down the road but it wouldn't go
over 25mph.

These are the notes from the mechanic...
In essence there is one or multiple electrical shorts and it is part of the wiring harness that
controls the engine fuel system. Once the shorts have been repaired, we’ll need to see if the
computer is damaged. This is a very time consuming job as the electrical schematic is
significant in nature. There is a good possibility this is not repairable.

Connected scan tool and check for Dtc found none at this point, performed engine balance
test, found #5, #1 and #8 cylinders not working, checked primary and secondary ignition
found bad secondary ignition, checked injectors same cylinders injectors not working
manually flow test injectors and those injectors dropping about 4 lbs with 5 ms time.
Checked power and ground signal and found no ground signal from pcm/harness.

Removed connector from pcm checked wiring from injector connector to pcm continuity test,
found shorted to ground with other wires at the pcm, removed wiring loom, and tape, cannot
find the short to ground, is going to need harness, and or undo all harness to find the short to
ground.

Hoping someone on here has some advice on what to do next. Thanks in advance!