What does a map sensor do and would it cause running issues ?

 

https://en.wikipedia.org/wiki/MAP_sensor

I replaced mine a year ago and didn't notice anything really. There was a huge following in the Durango forum (same engines) that saw MPG gains and response improvements. I also heard they get brittle or hard and don't work properly. Who knows.

 

Manifold Absolute Pressure. The sensors rarely fail, don't know if the lose accuracy over time though..... The little rubber elbow from the vacuum port to the sensor does dry out, and get brittle, and if it leaks, you get performance problems...... Easy to check though.