I have a 98 Cherokee Sport 4.0 5 speed.

So here's my problem I can start the jeep and let it idle and runs fine. I can rev it and everything but I go to start driving down the road not even 50 seconds it's like someone cuts the my ignition switch off and it dies. I go to start it back it will turn over and over. I turn ignition switch on and off a couple times and go to crank it it finally starts back up (also gas hand will drop to zero) I begin moving again (gas hand comes back up) i can go another 300 yards and it dies on me again i mean i can lay into it and boom like someone turns key back off. Check engine light comes on and goes off but its just says 02 sensor bad connection.

But like I said after I pull it into the yard and park it, and start it, it starts fine and idles fine and revs fine.

 

What happens if you put it in D with your foot on the brake? Does it eventually kill? What condition are your wiring harnesses in?

 

Its a 5 speed. Can't you read Radi? Dang. Kidding aside, I suspect fuel pump

 

Sounds like fuel supply; maybe pump or filter. Assuming the 'gas hand' is the fuel level gauge and it consistently drops when the engine dies there's an electrical problem causing it, possibly a pump drawing too much power assuming they share a ground source, or a faulty connection to both the pump and sender.

 

I've read that a faulty Crankshaft Position Sensor will cause fuel quantity indication problems. You may have a bad connection to the crank sensor, or an intermittant bad sensor.

Examine the crank sensor connector and it wiring as it passes over the intake manifold.

 

I agree with Ken.
Next time it just want to crank and not start try unplugging the CPS and plug it back in and see if it starts then. Also when you unplug it check the connection and make sure it's clean and tight. Some times when you unplug it and replug it it will doing this will get it started and will tell you that the cps is on it's way out. Also when the CPS goes out it will not put out a code.
BTW, If you do have to replace it only get an OEM one. It is very common that the after market ones are bad right out of the box and if they do work the have a very short life span. You can also check the fuel pressure at the fuel rail. You should have 49psi +or- 5psi. Let us know what you find.

 

Its raining today so it wont be able to check it out more till tomorrow I can get under it and check it out. I asked around and some people say it could be I have a bad ground cutting my fuel pump off (vibration while driving down the road) or I have a bad relay? Cuz ive if I get on the road and ease down the road (5mph or 10mph) it seems to do fine but once I start speeding up boom cuts out.

Last night I jacked up the back end and put it in gear and run it up to like 50mph and did fine.

 

There was no load on the engine with the wheels of the ground. This sounds like a fuel pressure issue. The fuel pump may be on its last leg, or maybe a grounding issue...maybe a fuel pressure regulator... It may also be a spark timing issue..

 

With a loss of fuel pressure and fuel quantity indication at the same time, and associated with movement of the Jeep, may indicate a loose or damaged fuel pump module electrical connector.

The connector is located under the Jeep, just forward of the fuel tank.

Crawl under the Jeep and closely examine the connector and its wiring. One half of the connector is supposed to be secured to the frame and the other half plugs into it. There are occasions where the lock tab on the connector breaks, or simply fails to lock in place. People have had to hold the two halfs in place with cable ties.

If it looks secure, unplug the connector and inspect the pins and pin cavities for corrosion.

 

Later models OBD2 fuel gauge sending unit connects to the PCM to help operate the EVAP based on fuel levels.

I had similar problems as you described with a 98. After replacing the sending unit the problems vanished. The fuel gauge sending unit is on the same 12 volt circuit as the fuel pump and also connected to the PCM. My fuel pump tested ok, the problem turned out to be with the fuel ga. sending unit.

Earlier XJs may have different wiring for the fuel pump pump assembly. 96 I remember feeds the gauge from the instrument cluster. 97+ there's connections to the PCM. The PCM uses the sending unit data to control the Fuel Gauge, EVAP if equipped and to prevent the OBD II system from recording/setting false misfire and fuel system monitor trouble codes.

As CCKen stated this type of problem may be only with the wiring, connections or possibly a sensor malfunction.

 

Maybe tomorrow if it dries up Im going to craw under neith it and exam my connects. Where do the fuel pump ground itself at? Ill keep yall posted to what happens

 

The fuel pump is grounded behind the spare tire mount. G302. See pic.

The fuel quanity indication system has no external ground.

 

Heh. My wife says I can't hear either.
Sorry, I completely missed that despite being in plain sight.

 

So about 90% sure that I found the problem. My uncle gave me a good idea, Run a wire from my battery straight to my fuel pump which would eliminate any power issue. What you know drove down the road and it ran great other than the HORRIBLE play i have in my steering wheel.

So I came to the concusion that it was my connector (from fuel pump to Jeep harness) had built up alot of greease around it. Guessing dirt had gotten into my plugend and was loosing connection why i was driving down the road. Just gotta really clean it out and get this bad gas outa the jeep and boom we should be good to go.

Thanks for all yalls help.