Hello I have a 2004 GMC Envoy 4x4 SLE with the 4.2 inline 6. It’s my wife’s car and when she was driving home today the car started to idle and run really rough. She was pushing the brake and it was shaky and stalled out on her at a red light, it has a smell coming from it I don’t recognize and don’t want to risk any further damage by driving it to the auto parts store for a scan. I recently changed the spark plugs and the BMR(blower motor resistor) I disconnected that just to see and it didn’t change. Has anyone had any issues with this?