280zxcandyapplered

i have a 1981 280zx non turbo. when my car warms up about 30 minutes or so it tends to idle real low and then just die. Some times it will start back up and other times it wont. I have replaced the ignition module, the dizzy, the spark plugs, the ignition coil, fuel pump, fuzes, and much more. Everytime i put something into the car it will act better for a couple days and then start acting up again. Many people say it is vapor lock. Any ideas? has anyone else had this problem? I just want my car to be normal again .:mad: thanks.