'87 dies upon lifting

My '87 4.0L AT has recently started to die after lifting off the gas while slowing to a stop or for slow corners. The problem is intermittent and is sometimes hard to reproduce. Upon dying, it's usually fairly difficult to get restarted though it will act like it wants to run. My first thought was low base idle and a sticky IAC, but I'm not sure. I haven't replaced the IAC, but I did increase the base idle.

The Jeep has no tach, so I'm not sure what the idle was before or where I have it set now, but before adjusting it sounded to be idling at the same speed it had since I bought it two years ago.

I drove it around for about an hour after increasing the idle speed and had no problems, but I'm not sure that it's fixed, because as I said, the problem is intermittent.

I've also considered that it could be the ballast resistor, but that doesn't really make sense based on the way it acts. I have a DMM, but don't know the spec, so I haven't checked resistence.

The fuel filter is new as of 6 months ago. I haven't checked fuel pressure, but I do have fuel present at the rail.

Is there anything that I'm missing? Does it sound like I'm on the right track with the IAC?

Good idea to clean the IAC before adjusting base idol.

x2 on the IAC, and I would check the TPS for correct adjustment for good measure.

With the auto you are looking for 700 to 750 RPM idle, transmission in Drive. NOTE: when attempting any adjustments or even checking the idle with you anywhere other than in the driver's seat with your foot on the brake you need a second body. NEVER trust the parking brake or wheel chocks to hold the vehicle.