As the guys have said above, it appears to be the crank position sensor, the reason I say this is I just replaced mine today after having similar problems and it appears to have fixed them. Another thing that I did even though it wasn't necessary, was replace the capacitors on the ECM. The reason it wasn't necessary is because it didn't fix the problem.
Autozone has a BDW crank position sensor, that is made by Delphi for 63$ Autozone Part #SU368. I would replace that before the capacitors, because it is a whole lot easier.
Keep chasing those Jeep Gremlins you'll catch them by throwing money @ them.