Well some would not repost in this situation but I realize I am human..lol.First off I am a mecanic but I do Industrial machines and have worked on alot of autos but I am old school back when we had points and carberators when they came out with efi's and computers on them I kind of gave up.Any way I was looking up just where this plug was to pull the codes and found out it was in the console between the seats..BAM..a light went off in my head..I was washing my truck last sat in the yard and pulled the cup holder out to clean it..there was a large black plug and beside it was 2 wires both where white w/a blue stripe and yellow rings around them, one of them had a male end and the other had a female end..I figured they was supposed to be connected sooo I connected them I also told myself that the next time I started it if it done anything wrong I would remember this.well I forgot.after this light bulb went off in my head I went out there and disconnected them,man It runs better than it ever did so I must have had a muffler problem all along but it sure runs good now,I know I am a dummy.does anyone know what these 2 wires are for?self diagnosis maybe?