So recently I just did a bunch of fuel system work on this 5.3 Silverado. Pressure regulator, fuel pump, fuel filter, map sensor. And it ran fine for a while but then it randomly just does not want to start. Usually after it has been sitting for at least a few hours.

One day my wife called, said it wouldn't start at the grocery store. I borrow a car and half way there she calls and says that it started.

It turns over fine and with starting fluid it will run long enough to burn the fluid.

One thing I haven't done yet is correctly solder the wires to the fuel pump. I just used the crimp connectors that came with the new harness. So that would be one guess. I did wrap it very well with heavy duty electrical tape though. I have a hole cut for access to the pump so I can get back in later to make the correct connections.

Also I have been getting codes the 2 obd codes that would indicate a vacuum leak. But usually the ses light only stays on for a few minutes before going away.

Any thoughts?