My 94 Cherokee Sport starts fine I drive 1/4 to 1/2 mile and it dies like its out of gas. Sit for about half a minute it will start right up, go about same distant and stalls out again. I changed fuel filter Crank Position Sensor and fuel pump less that 1 1/2 years old so leaning towards fuel pressure regulator. Is that a good possibility or does anyone have some other insight? BY the way I'm new to this forum not sure if I have the right posting location Sorry!

 

Welcome to the forum; you are in the right place for help with your 94 XJ.

Would be nice to know if you're losing spark or fuel or both when this occurs.

One thing you could do is to put a fuel pressure gauge on the schrader valve on the fuel rail, start the engine and watch it. Should remain pretty constant at around 31 psi.

BUT: Just because the crank sensor was replaced 18 months ago doesn't mean that you can rule it out as a possibility. Especially if the sensors you used was aftermarket and not OEM Jeep. No lack of people having reliability issue with some (not all) crank sensors. If you do end up replacing it again, buy it directly from Jeep for best reliability AND longevity.

Without further testing, (recommended to help isolate this further) there is some guesswork but it is very possible that you are experiencing "thermal failure" of an electrical component.

*The #1 cause of this is a faulty crank sensor.

*The #2 cause is a faulty ignition coil.

Both of these components can be tested with a meter, but you'd have to be quick and test them when the engine doesn't run, testing them when the engine runs may yield no clues. And with your engine starting up 30 seconds after it kills, this makes it virtually impossible to test unless you were to use a hair dryer on the component while testing to replicate a HOT condition. Test, blow dry, test, blow dry........if the component is shaky, heating it up can sometimes yield that out of spec measurement that I'm looking for which necessitates replacing that component.

Stay close to home (how about your driveway!) until this is resolved. A catastrophic failure of this component is not likely far in the future....

 

Yes I ran pressure test it stayed fairly constant 312 psi. And about 39 psi with vacuum tube removed fron Fue l Pressure Regulator. Pinch fuel return line and shut engine down lost about 20 psi in 30 minutes to rule out pump. I can idle all day long and no problem. Reved up for 20 seconds or so to about 3000 no shut down if i drive back and forth at 10-15 no problem but get on road at 20+ it turns off in 1/4 to 1/2 mile like its fuel starved. Sometimes when I crank it right away after shut down it will chug a little. I have a new FPR coming tomorrow, believe it is oruiginal equiptment, theres about 280,000 miles on engine. Thats only thing I haven't replaced, so its due whether the problem or not. Would crank sensor do that off and on thought they just shut down completely . Thanks for Insight so far!!!

 

Crank sensor can fail catastrophically, be intermittent, or suffer "thermal" failure. That is why it is absolutely still in play here...