My 1992 jeep cherokee sport inline6-4.0L idles rough and stalls when warm...

Ever tune it up? ever , or at the 60k mile points?
if not why not.
does the CEL lamp glow running>?
rough idle is called misfire.
stalling can be many things, a mech sees this all in 5min.
here on the form i have to ask many questions (cant drive it)
lets play that out.
1: i start car and ask owner, ever tune it up,: blank stare.
2: i see it dont reach 180F coolant temp,. (bad thermostat)_
3: then note misfire. i tune it up and its fixed. or
4: it still misfires,, i find the EGR stuck open. (listed under service 60k)
5: it still misfires, i find idle too low, the ISC is stuck closed.
i clean the EGR and ISC valve and car now idles ok,
but is still rich , i find the 02 front sensor long gone bad.
it looks like it has cancer.
there are over 50 causes for misfire,
1 or all 6 cylinders. what we do is start with basics and work up.

here are 2 hints on stall.
first off the ECU failed to stop the stall, its programmed to do that
using the ISC .
so it failed to work.
the EGR stuck open will do that every time or idle at 500RPM
and shake the engine hard, misfiring.
or if one cylinder or more is dead.
or if the ISC sticks closed.

so when it seems to stall, pre-stall, as RPM drops below 800 rpm
you use a fast right foot. is it easy to prevent the stall?
easy,save, is isc stuck closed? gummed up.
harder is EGR stuck open, (but you can correct it by hard actions of right foot)?
impossible to stop the stall.?

your mech, does all that action in 5min. flat.
even loss of 12vdc power to EFI systems , do this.
(cant save it) and mech sees dash lights go dead. bingo no DC power, all by looking and seeing. and feeling.

he gathers evidence,


both my 4.0L jeeps, loved to stick the ISC.
every 20kmiles, off it cam and got sprayed with
Klondike gun lube, Dry lube. no oil , it looks like brown paint
and acts like Teflon.
The 4 liter likes to get he PCV oil mist up to the ISC,
this builds a film of gunk on the valve cone inside .
im not saying this is it, but the easy save above is a big clue.