Good morning, found 1 of my 02s on bank 1, It has 2 white wires 1 black and 1 grey. Now can I test the sensor with dc volt-meter, using black and grey wire and a torch (bench test). Now if that's not the problem, I'm going to try and find intake leak, I have heard that a propane torch can be used for this, sounds crazy! So what's the right way to test my HO2 sensor & for intake leak, the code was P1131 1998 merc. Mystique?