I changed plugs,rotor, cap,and wires.my 90 camaro rs 6cyl was just running away and I had no speedpmeter. I checked the codes and only got a 12 over and over. I went back over everything and looked at connections and tried driving it again. It was fine for about a mile; then the speedometer went, but this time the car has just stalls on top of this now the air won't work when the speedometer goes out. Is there a fuse I'm not checking? Any ideas? prayers to New York