My '91 4.0L has been "bogging down and stalling".
This hasn't happened when I drive, but when my brother (who takes it to work daily). However, he said it bogs down and eventually stalls.
Before, he said he would disconnect & reconnect the spark plug wires and it started. So I replaced the dist cap, rotor & wires. I replaced the plugs back in September & there's less than 4k miles on those plugs.
However, he said that it's happening now and if he doesn't wait a while, he has to give it gas or else it'll die. After a few minutes until it starts up again and runs fine.
I can't replicate it, and I don't know what it could be! Whenever I drive it, it drives wonderfully and I never have any issues. But he said it happens to him a lot.
He drives 30 miles each way to / from work, and I only drive less than 10.