My 91 4.0 With AW-4 has been downshifting while i slow down and when i get to a complete stop it is trying to die and sometimes i get a hesitation when i try to get going again also notice when you put it into gear it will try to die to. It only does this when it has been warmed up the downshifting might be normal for this but i don't know other than this there is no other issues that i can tell and i'm not getting a check engine light. the Idle does come back at the stop it just does it once each time.

1. Always review tuneup hardware when symptomatic. Plugs, plug wires, distributor cap, rotor.

2. The throttle position sensor (TPS) is involved with transmission shifting characteristics and smooth acceleration. I would test yours. You'll need a manual and a meter (analog meter works best).

A chilton manual right?

Hard to say if a Chilton or Haynes manual has this procedure. They are notorious
for not being very comprehensive. But they are cheap and widely available.

You can find them at almost any parts store.

Personally, I love the factory service manual (FSM). They are not cheap but they
are 100% comprehensive and are tailored to only your year XJ. You can sometimes
find them on ebay at a reasonable cost.