Engine code and running weird

[XJtheXtremeJeep]

OK so my 96 cherokee is throwing code p1391 its a cranksensor code (intermittant) the jeep runs fine until it is warm, after that the rpms jump all over the place, theyre the worst at around 2000 rpm, only does it at operating temp, if any one has an idea whats going on or what it could do please let me know

[1cleantj]

http://autorepair.about.com/library/faqs/bl850d.htm

[XJtheXtremeJeep]

thanks, i read this before but just dismissed it as i had been told that there wasnt a camshaft position sensor so i concentrated on the crank sensor.. but now ill change out the distributor/sensor and see what happens