Will not stay running?

That description sounds like a fuel pump issue. Try this test and reply back with what you find. Turn the key on, not start, wait 5 seconds and turn it off, repeat this about 3 times and try to start it. Does it start and run or does it start run about 3-4 seconds and then shut back off?
Next look at this guide on testing fuel pressure. The pumps and wiring on that vintage GM are prone to problems. The most common is the pump failing, closely followed by the wiring to it.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Hello,

So it will start up and immediately stall?
Is there a check engine light?
Trouble codes can help point us to the right direction.
There could be a number things that could trigger this issue.
An engine will need spark, fuel and compression to start and stay running.

You could have a faulty crank sensor.
It can also be that the fuel pressure drops due to a bad regulator and the engine stalls. Could even be compression issue.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please if you would let me know little more details of what the vehicle is doing.

Thank you.

Check to see if you are getting fuel pressure. It sounds like either you are losing fuel or some type of sensor issue, which stalls the engine.
Also is the check engine light on?

What does the security light do when you try to start it? Starts runs 2-3 seconds and stalls is also an indication that the security system has tripped and it is shutting off the engine, would also explain the lack of throttle response. Do you have a second key you can try?

Okay, put the key in and just turn the key on not to start. What lights on the dash come on and go off? The security light should come on and go off if it is reading the key properly. If it comes on and stays on, or flashes you have a security issue.

Okay, then the issue isn't directly fuel related it is that the security system has detected a problem and is shutting off the fuel system as it thinks the truck is stolen. With a flashing security light it means the key is not being detected properly, in the case of GM vehicles that is usually a fault in the sensor that is part of the PassLock system. The sensor is built into the housing that the ignition cylinder is in. To replace it you need to take the steering column apart to get to the housing and the bolts that retain it. Then replace the housing and do a 30 minute relearn process to get the security system to turn off. Replacing the housing is a bit different depending on the actual column in your truck, if it is a tilt column and if it's column or floor shift.

GM 30 Minute Learn Procedure
Turn "on" the ignition
Attempt to start the engine, then release the key to "on".
After approximately 10 minutes the telltale will turn "off".
Turn "off" the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes.
Important; the vehicle learns the PASSLOCK Sensor Data Code and/or password on the next ignition switch transition from "off" to "crank". You must turn the ignition "off" before attempting to start the vehicle.
Start the engine.

Before I replaced the housing though I would get a dealer level scan tool and use it to check the security system to see if it shows anything else wrong first as it could be an issue in the body control module or the wiring as much as the sensor itself failing.