2003 gmc envoy_sle
Have you checked the OTHER END of the positive cable and see if there may be a problem on the starter solenoid stud may be being broke and moving around.
If the stud where you attach the + cable to is broke loose and not making good contact with the wiring inside the solenoid, yeah, from heat and/or vibration.Went out this morning and it started right up. Ran for 10 minutes and died. Went to have the battery tested and it was low so just went ahead and bought a walmart one for $60, hooked it up and nothing. Not even a click.
Starter is my next guess but would that cause it to shut off while it was already running?