Error code 31 is a MAF issue on the tsrm, but I read elsewhere that for JDM swaps that it is related to the MAP sensor. But from there on i don't know how to exactly to find out what the problem is. It just popped up the code one day as soon as I started the car. I even reset the ECU to check to make sure it wasn't a random code, sure enough it came back on and my idle is nasty. Where do I go from here? Can i use a volt meter to test it's resistance, power, and whatnot?