Just bought a 93 3.9L Dakota and have been driving it for several weeks. Noticed the mpg's seemed very low. Checked codes and showed a 13; wh/ appears is basically for a faulty MAP sensor. I've already changed plugs, wire, cap, rotor, air cleaner. Will the MAP sensor, if bad, cause me to be getting 13.5 mpg. Just curious if it also be an o2 sensor that is on it's way out. Thanks for any help!

 

The map sensor is important. It is easy to replace. Yes it can affect gas milage as well as histation and power. Your o2 sensor could be going out too, but replace ur map first. map $40, o2 $70

 

Thanks for the reply. Since the truck threw the code for the map sensor I'll probably just change that out first. If problem is still there then I'll look at theO2 sensor like you were talking about.