When I start my Jeep it idles fine for the first couple
of seconds but then it starts to shake a little and
idles back and fourth
You're lucky it still runs , its 20+ years old . there's a ton of maintenance that has to be done I imagine .
By your description, sounds like your running lean on fuel. They changing oxygen sensors, spark plugs, and spark plug coils, See if that works. Best thing to do though is first go to AutoZone tell them to check engine light. They will tell you where to start. It is free of charge.
Did a code reader, several misfires and need governor pressure sensor and the down o2 sensor I think?