I have a 2002 Chevy Impala LS 3.8L V6. It has 202,000 miles on it (yes it's driven alot). Recently the engine has been dying after it warms up. It will run fine until you drive about 10 miles on the highway. Then the engine will rev itself up to about 5,000 rpms briefly and then the engine will die. The engine will then not start anymore until you let it sit for awhile (like a day). Then the it will start back up and do the exact same thing. We flushed the fuel lines, checked the fuel filter and had the catalytic converter replaced (the guy who replaced the converter said that it was just powder when he removed it and stated that he never saw one like that before). I know this engine has 202,000 miles on it, but they are all highway miles and this engine should have another 100,000 miles in it. Does anyone know what might be causing the engine to do this?