need help,car dies,then starts right back up

With the miss and the random shut off and restart you are more than likely going to find it is either the camshaft or crankshaft position sensor. Other than waiting for it to get bad enough to throw a code or hooking up an ocilliscope to it to look for an irregular pattern you are going to have to replace them. I would start with the camshaft sensor as they usually will be the first failure. Not sure if Chevy is a picky about their sensors as Chrysler is but on a Chrysler I will only use an oem. There are a lot of out of the box failures with the cheap auto parts store ones that can have you chasing a phantom problem due to a defective new part