Car was running rough, had a 13, 23, and a 32 code. I changed out the O2 sensor. I removed the EGR and flushed it out real good. I removed the throttle body and plenom and clean them out as best I could. The throttle body came out nice, the plenom could be much better.

Car has a lot better acceleration, but I still got the 23 code for a MAT sensor, plus it feels like it stutters when your crusing at a steady speed, 40-50. In the haynes book it doesn'y show a MAT sensor, is it the one in the AIR BOX and would this cause this problem?

APPRECIATE ANY INPUT, CAR IS DRIVING ME CRAZY!!!

 

I am assuming this to be a V6 car? If so, then yes the MAT sensor is located in the air box. Its on the back side towards the headlights on the box. And yes if this sensor is bad, it can throw the ECM into fits. Not like a coolant temp sensor though. That one is even more important.