Went to start my truck Sun morning and it idled very sluggishly. When it was given the gas it hesitated. Applied brakes and it died but started right up. No warning hadn't driven it for a couple of days, driving rain the day before. No other engine problems before this. Thank you GMC sierra 1500 1999 4x4 V-8

it's old, 20 years.
needs service big time and overheating that bad is never good.
tow it to shop , pay for diagnosis.
or RTM
https://eautorepair.net/Marketing/Default.asp

1: a full compression test and leak down test is , needed first.
2: then spark tests, or new spark plugs and boots
3: and fueling tests. lots even bad fuel, low fuel pressure ,etc.
the CATs don;t just fail/good;/fail/good. never.

the cause of overheating must be found. and the cure for any overheating damage,
lacking tools and skills , ? check fuses.
in the morning dead cold engine only, OFF the RAD cap, must be full UP of 50% antifreeze (not water) or it will overheat.

Post next that you did change the fuel filter and the fuel pump. The computer won't get the fuel issue.

Fuel filter clogged, weak or faulty fuel pump. Have fuel pressure checked, if its ok, then check igniton coil or module.

the question is-- was you foot on the brake at home or was just the hand brake applied
when driving , slowing , stopping standing , all have the foot on the brake which is activating a brake booster and if that is faulty , the vacuum leak causes the problem

sounds like you have a egr that is stuck open
remove the egr valve clean it and see if that helps
of not replace it should improve the idling

possible blocked fuel filter or fuel pump not supplying enough fuel (starving) check fuel pressure with pressure gauge
also blocked exhaust or cataletic convertor can cause same issue

Take the car for proper diagnosis. Your alternator must be bad.

Fuel pump

my ram 50 starts just like any other vehicle, (no light switch pulling whatso ever), it sounds like somebody haas rewired something wrong or you have a loose connection and when you hit a large enough bump it cuts your power. Start it up and find a speed bump somewhere and drive over it enough to give your truck a jolt and see if it dies.

have you checked out your fuel filter? I had my 2003 denali do the same type of problem and it turned out to be a very dirty fuel filter.