its wise to learn to do basic checks on sensors, such as map, and O2, but they are not always very conclusive without an oscilliscope

google "how to check cherokee xj map sensor" etc etc

for a suspected vacuum leak, a visual inspection, then vacuum gauge, spray some ether-type starter spray around suspect areas

I am not usually one for the parts cannon, but with a TPS and front O2 sensor, they have a lifespan, and if an OBD2 fault is showing, I would replace the indicated sensor
If that doesnt work, you now have a spare

You could try unplug front O2 sensor and see if that makes any difference, or throws a new code or not