unknown plug issue

i have i plug that is just sitting to the drivers side of the valve cover , and comes out of what i would call a main harness, that runs between the valve cover and the fuel rail. i have looked for the other end- to result in none found. can u help me and tell me were this goes, and how important this is.
Thanks,

heres a photo of it

Do you have an '87 - '90 with a 4.0 and a stick?

its a 1987 4.0L with a AW4 transmission, anyone have a clue ?

OH wait, I bet I know what it is...

You've got an '87 so you'll have hte C101 connector. I'd be willing to bet that's the original lead to the Crankshaft Position Sensor (CPS). With C101 equipped Jeeps when replacing the crank sensor you're supposed to bypass the C101 connector in wiring it up.

yep... that is the by-passed crank position sensor harness... forgetaboutit!