I have a 87 XJ with a 4.0L and it will only stay running if I turn the key switch almost to the start position without engaging the starter. As soon as I let go to drive it shuts off. I can't even push the gas and keep it running. It is at a friends house right now, but I am not sure what it could be because my brain is worn out thinking about it!!! Please if you have any ideas let me know. Key cylinder,ground wire??

 

The switch maybe messed up. You may want to start there they are only about 20 bucks. If that aint it, i may be a ground.

 

my geuss is to check with the renix god.oh yeah he is the the almighty of the renix. but to me sounds like the switch at the bottom of the colum ist getting proper ground or the acuater rod is not foully ingageing. dont know thats wht i would check out.