Intermittent rough start up on 01 Buick Lesabre

So I have a 2001 Buick Lesabre with 185k miles that acts a
little quirky sometimes. Every now (i.e.rarely) and then the
car will start up rough and the engine will stumble like it
wants to stall. Then after about 1-2 seconds idles like
normal. 3 times it has actually stalled out (at startup only)
and required me to turn it over again (in a total of 1 year of
ownership). If I give it a quick little tap of the gas that will
prevent it from stalling in those occasions and if the engine
is running rough at startup a little a quick little tap on the
gas settles it out. Again what is weird is it doesn't do this
everytime. 90% it fires up no trouble. And that 10% it
chokes a only little but settles out within a few seconds and
is back to normal. Once it running and idling it runs great.

No dash lights come on and the computer has no codes
either. Any idea what could be causing this bizarre issue.
Other then that the car runs great, and is reliable.