fuel

Hey guys, My 2000 cavalier's been acting strange. After the gauge drops below 50%, at random points, it will shut down as if it's out of gas. If I wait a second, I can restart the car and it's fine. Sometimes it goes another 10 miles without a problem, others it occurs with a mile or so...

So the other day I filled my main tank on my truck. Drive to work and when i am ready to leave i'm at half a tank. Switch to my aux tank and it is now half full. My uncle had the truck for 4 months and swapped the original pump with a pump from an 84' which has a return line that has been capped...

1999 5.7L 2WD Suburban has 180K miles. Runs great. never misfired. I use Techron every 5-7k miles to clean injectors and fuel system. Started with no problems. Then it took two cranks to get it to start. 2 weeks later my wife started it, drove it. went to restart. Car cranks, not starting...