89 firebird v6 auto, check engine light comes on after driving for about 15 20 minutes and goes off when turn off the car and crank it. It like to cut off on me at a stop light when i'm sitting there a couple minutes or when I'm slowly turning into a parking space or such. I checked the codes using paper clip it gave me 12 12 12 32 32 32 12. I bought the car a couple months ago. It had a bad fuel pump so I put one in doing it the hack way by cutting a hole in the trunk. I'm running good gas v power from shell. I have replace thermostat, plugs, air filter, fuel filter, radiator fan motor and relay and temp switch, oil changed, front end alignment, It runs fine but the rpm's like to go up and down and it cuts off when stopped and I have to give it gas for a few minutes when I first crank it or it will cut off immediately.