Truck Repair: 1998 454 Chevy engine, difference weather, vacuum leak

Question
engine starts perfectly sometimes.  Other times it takes 6 or 8 turns before it will start and it seems to be starting rich. No check engine lights have come up.  Wires and spark plugs have been replaced.  Fuel pump pressure checked.  

Answer
Hello Mary,
Experiment with it, and see if it makes a difference weather you have your foot on the brake or not.
It may be acting like a vacuum leak when brakes are applied.

Also, see if you can hear the fuel pump run inside the gas tank every time.

Van