Stalling at lights and speedometer working intermittently

Two problems:
1. Randomly while sitting at a light idling my jeep will just stall. I put it in neutral and it starts and runs with no problem. Highway driving everything works fine 99% of the time. 1% (while in lower gears) the truck gives a jolt almost as if it is skipping a beat and then continues to run fine.
2. The speedometer works intermittently, but the tachometer gauge works perfectly. My mileage does not move when the speedometer is not working.

Love the vehicle (we actually have two from the same year). Would like to fix these issues. Any help would be greatly appreciated.