1998 Jeep Grand Cherokee Stalling Problems

It's your oxygen sensor. These Jeeps have 2, a forward and rear sensor.

Everyone is on about how its this module or that module. 95% of the time, its one or both of the oxygen sensors. The forward one is placed in a poor location and gets a lot of wear from road and car wash spray. They cost around $100 each. Don't try taking it off yourself. Chances are it/they are heat welded to the exhaust.