Are you getting any DTC'*?
If not I'd inspect all soft vacuum lines, my 96' PA had a few that had dry-rotted after 15 years, one in the back rear underside of my car (the fuel vapor EVAP line) even disconnected from being so dry-rotted.
If you do not find any dry-rotted hoses I'd get some MAF cleaner and clean that MAF off, if the MAF'* thermistors are a bit dirty it can read a little low, which if it reads too low at idle it can stall, because it will be starving for fuel.
While cleaning the MAF you may as well replace that air filter, if you have not done so recently.
Have you tested your fuel pressure?
2006 Pontiac Grand Prix GT with SC
1996 Buick Park Ave NA