i am having trouble with getting trouble codes out of my comp. with the scan tool that i have. when i plug it into the aldl connector the service engine light will come on but i don't get any flashes at all. it won't even flash the 12 code. does anyone know what i need to do to get the tool to read the codes? I am having ignition problems when the motor starts and runs for 2 or 3 minutes and start missing and backfiring throught the exhaust. then it will quit and when you try to restart it there is no fire to the plugs or the coil. I can't get any fire anywhere until it cools off then it will start right back up and do the same thing again.

 

You did not specify the year, but if it's an OBDII car and you are trying to use a autoparts store scanning device it won't work. Get something specific for that year car.