at stop sine it die's some time's but strats right back up on 1999 Buick LeSabre

some time 's then other time's runs good for day's

2 answers
Check for any codes, does your yellow service engine soon light ever come on? If so, get those codes!

here are some shops:

https://repairpal.com/directory?address=52653&car_brand_names=Buick
It could be your fuel filter is clogged, or maybe you need to replace the fuel pump. Get it tested, good luck