Code 14 could be one of two codes - MAP voltage high OR low, as Wayne said. You need to figure out which one is going on before doing anything else. The MAP sensor should be getting around 5v supply. You do need a voltmeter for this. Just buy one, they're cheap. It'll be a lot less money for a meter than a new sensor. At $90 a pop you better be sure the sensor is bad first. A meter can be had for $20.
Anyway, if you get one, unhook the connector to the sensor, put the red meter lead into the 5v supply wire, and black meter lead into the ground wire on the connector. You should be getting around 5v. If you are getting more, then the code is "voltage too high" if its low the code is "map voltage too low". Also check the little rubber hose under the sensor that pulls vaccuum off the manifold.
Your best bet would probably be to get a haynes manual to help you along. Autozone can also scan your codes and tell you exactly which one of the two you've got. But what fun is that?
Here's a diagram of which wire is what on the MAP connector. Your is the top one - XJ body.
SimpleXJ