I just changed my plugs and wires on Tuesday after my car had 300 code. The car has been running awesome for the last 2 days, but this morning when I started the car is sounded to be idling a little rough. When I started driving it seemed to be running fine but the CEL started flashing, and came on again. I reset the computer by pulling the fuses I needed to so I am confused. Does this often happen? Also, when I sart the car with the AC on and the car warm, I get a burnt smell coming from the vents. Any ideas?