Engine dies under power?

I have a '94 XJ County with the 4.0 HO engine. Automatic, PS/PB, cruise, Selectshift, etc. Mileage is 119K. The problem is a "sometimes" problem with the engine. It will buck or act like it is shutting off and then instantly restarts. This usually happens under acceleration and usually on the low end like starting from a stop. If I hold my foot down and try to drive through it, it just continues to buck on and off. If I let up and drive slow it will smooth out. I can usaully drive it home OK but if I give it too much throttle it will buck again. Now here is the strange part. It doesn't always do this?! But I have noticed the problem is more frequent when I have a low fuel tank!!? I thought it was maybe fuel just running away from the pump pickup but this has happened with almost a half a tank of gas. If I keep the tank full or above half I don't have a problem so it must be a fuel problem. I have replaced the throttle position sensor and replaceed the wires/cap/rotor and a new air filter. I added fuel cleaner to the gas. These seemed to help but the problem still exist. I'm wondering about the O2 sensor or the cat converter or fuel pressure? Any help would be appreciated.

Change your fuel filter. I don't really think this is your main problem but it will cure some of it I am confident. next is to have a pressure test of your fuel system done. You could have an intermittent problem that just won't show up until something just "gives out".

I forgot to look at the year of your vehicle but if it is 96 or newer you can go to autozone and get a "chip" that plugs into your obd2 port and scans the computer while driving and it saves the data so you can check it on your desktop computer and see what has been happening; it's pricey but woryh it for intermittent problems like yours.

Hope this helps some.

JC95

You might wanna consider the possibility that your fuel pump is intermittently giving in on you. Check the fuel pressure at the injector rail while the engine's idling. Hopefully it'll act up on you at just the right time and then you can see if the fuel pressure has dropped.