'99 GMC Intermitent Elex Shutdown

Vehicle: '99 GMC K1500 Suburban w/ 5.7L

Problem: Intermitent electrical shutdown (dash cluster, lights, radio, etc.) Episode usually lasts for about 1-2 seconds before electrical restores. Here’s the crazy part: It doesn’t always happen, but when it happens, it occurs:

--shortly after starting the vehicle, then

--backing the vehicle (as in leaving the driveway), then

--the moment after I place the truck in “drive” and begin to accelerate, then

--as I am turning the wheel (say, to straighten up after a backing turn to right.) When the above steps occur, zap: everything shuts off and comes back up a moment later. Thoughts?

How did you visual inspection turn out? battey and cables(check for acid leakage/damage at postive terminal) engine and body grounds,wiggle fuses in fuse box,has engine been out?all grounds re-connected? just grab stuff under the hood and start wiggling to see if you can induce problem (have someone watch lights)is the big cable at the starter tight?(these are often loose)Has the harness been hacked into for radio or alarm?