First of all in such cases if your check engine light is on then there is a code that needs to be scanned,this could be related to the problem here.Anytime a check engine light comes on this means there is a problem that needs to be checked into.
On most of such cases the problem is noticed due to egr valve that is partially stuck open as this will lower the idle slightly and may stall out the engine.
In case of faulty egr valve the engine will idle slightly rough and possibly cause the truck to shake.
On GMC sonoma egr valve,it is located just in front of your engine throttle body and right in front of the upper radiator hose where it connects to the top of your engine.
Another faulty part can be idle air control motor
That can also cause the low idle and stall.
Visually see if there is any kind of carbon build up in the throttle body bore where the throttle plate is,if you see then get the throttle system cleaned.That carbon build up can cause restricted air flow into the engine at idle and can also cause this.
Now to start your problem troubleshooting,first check by removing the air intake over the top of the throttle body,then take a cloth with some carb cleaner or brake cleaner on it and wipe out the throttle bore with the throttle plate open as best a s possible.Then see if it idles normally and if the stalling is gone.
If it is not then the idle air control motor and Egr valve will need tested with a tester and a scan tool,if found faulty it will need replaced.
Most likely this will either be carbon build up in the throttle body,or a faulty idle air control motor or egr valve.
Get these possibilities checked,these will help.
Thanks.
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