I have a 07 Sierra and I drove today about 25 mi then it starts cutting out and eventually dies that is at 75 mph then wouldn't start for about 2 hrs when I got it started drove it back home at 60 and it did fine I don't know what is going on put a pressure tester on it for about 30 seconds and it read 59psi I don't know what it is. fuel pump maybe any ideas??????
