Ok, I pulled the code and it gave me an 0803 Absolute Pressure Sensor.

Can someone tell me what this is, what does it do. And where this sensor is???

 

It's your absolute pressure sensor. It senses air pressure in the intake. It's on your scoop/snorkel/whateveryouwanttocallit.

Did you search at all? You didn't even need to search, there's a thread about this exact thing on the first page. http://forums.maxima.org/4th-generat...i-looking.html

 

I realized it wasn't plugged in fully after I did the whole clutch change.

I plugged it back in and did a reset but the code came back up again.

Prior to the clutch change I didn't have a problem at all.

Could the switch have gone bad somehow???

 

It's possible you damaged it. The SSV isn't listed as a possible cause for P0105, only for P1105.

I'd try a junkyard boost sensor and see what happens.

 

went away after driving 15 miles