truck threw the code for cyliner #2 glow plug (P0672)and the code won't clear. is this a replacment i can do in the driveway or should i take it to the mechanic/dealer? the guy at my tire shop who read the code said it was likely an over-amperage issue whereby the plug hasn't failed yet but probably will. if it fails, can other damage occur? surprisingly, i didn't see any how-to's in the tech folder for this one. thx