Help me please

I have a 1996 Jeep Grnd Cherokee Lmtd v6 4x4 with 132000 miles. Recently I have started to experience problems with the vehicle stalling. I have taken it to, two different mechanics who have done diagnostic testing on the vehicle. Replacing crank shaft, pick up, and ignition sensors. Fuel pressure was checked because when the engine starts to fail the gas seems to be the main issue as if there is a lack of. But the pressure was fine. I was told that exhaust manifold need to be replaced so I did this as well. Fuel filter has been replaced and one mechanic went as far as replacing all spark plugs and changing out filters. Still the vehicle is stalling. Now there is an added plus to this story, sometimes the jeep will turn right back over, at other times it has hard starts, where engine will turn over but stall out seconds after or whine with no start at all. I am at my witts end, a new ideal or suggestion would be much appreciated. Thanks