stumble! ideas?

94, 4.0, aw4, 231. Cruzing at 65 yesterday my xj stumbled 4 times briefly. Didn't die just stumbled just kind of a bump bump then fine then again about every few seconds three more times. It ran fine the rest of the day then in a drive through this morning foot on brake at idle in drive it stumbled again only once then fine. Did this a few weeks ago then fine till now. Thoughts ideas? Reading abouts sensor testing at this moment for ideas. Any input would be great. Thanks in advance of all info provided and snide remarks as well.

Could be anything.

Onset of thermal failure of the CPS; bad grounds; voltage supply issue; fuel supply/delivery issue; o2 sensor.

This is the "curse" of the intermittent problem--they present then go away before you can test everything.

Problem solved!! I new it was a matter of time before I caught up with it. Can position sensor. Drove around quite a bit, got home to get parts for work amps no start. It tossed a code 54, I tested cam sensor and no worky replaced and Viola runs again.

that's got me thinking- that probably is what was wrong with my 1991-
That's about all I didn't test or replace (kept thinking Crank/ not cam sensor)- before I realized my frame was cracked along with all the absent metal that was replaced with rust over time- I decided to use it as a parts vehicle and purchase a 98 xj. Though completely stock- the 98 is has some quirks and benefits.
My stumble by the way- started just like that- almost could have missed and not noticed it- then it did it more and more when hot (un-drivable/safe)- now moving it around the yard/driveway it does it cold too/ immediate on start up. So progressively worse.