I do also own a couple Jeeps.
A '86 XJ that I have swapped a 5.3 into with a 14B and D44. So I bought an '91 XJ Sunday, here's the story. Drove 2hrs get to his house, it's sitting out front, looks good. Started it up, runs smooth no knocks or noises, let it run a while and asked a few standard questions. So took it for a test drive, running good the 1-2 shift is delayed but shifts good when it does finally shift, no worries. Get 4 blocks from his house, stop at a stop sign, take off and it dies. I coast off the road when there was a turnout for mailboxes. It won't start, it tries but won't run. Spent 15mins trying. He apologizes as we start walking back, he apologizes a few more times. Almost to his house and I make a low ball offer on the condition we can get it on the trailer. He counters(still way low) and I accept. We drive back to the Jeep, I back the trailer up to in front of it, get the ramps setup, try to start it, it starts and dies and rolls right up to the ramps. I try again it fires and I drive it on the trailer, it dies. I hand him the cash, he hands me the signed title and then he just drives off. Wow. So I strap it all down for the trip home, try to start it again and nothing. All good. I get home thinking about what's up. So tonight I connect the fuel pressure gauge to the fuel rail, turn the key on, no pressure, no sound of the pump, nothing. Time to get the voltage tester out. Turn the key on crawl under the tank and check for voltage at the plug, nothing. Hmm, well I'll disconnect the plug and check to see if there is voltage on the supply side. As I grab the plug it literally just unplugs, so I reconnect it. Crawl out from under it, turn the key on, the sound of fuel pump, fuel pressure and then it I start it right up. During the walk back he had mentioned he thought the fuel pump was going out.
Now to see what else needs attention. It was a good day.