What is the function and how can you tell if it's bad (ohms/volts readout please.)

 

On the N/A, it helps the ECU determine timing, and when to engage the secondary injection system.

 

thanks j-.....all i needed was a simple answer and went through umpteen posts to no avail, i was asking because i see a lot of cleaned up engine bays with teh pressure sensor removed......do you have to run with it...?

 

I think it does more then that. you can run without it with a standalone I am sure

 

If you see the pressure sensor gone, then it's most likely a car running some sort of stand alone EMS. Unless you plan on doing the same, I'd advise keeping it on.