1990 Jeep Cherokee Laredo straight 6 4.0 L

I ran into a little problem earlier today and I quite haven’t
found a solution to my problem yet but my Jeep will crank
but not fire up. I looked at the alternator and battery first
both were fine. After I checked those I was able to get it
running but now it has started to run rough and barely
holds an idle. Once it gets warmed up it idles normally but
then after about 15 minutes it does again. I checked my
cps sensor and it’s fine and I unplugged each sensor and
sprayed it with electrical cleaner but still nothing happens.
I’m out of ideas of what it could be. You could say I’m a
little more than stumped?