97 blazer won't start at certain temps.

My 97 blazer will not start at certain temps. It will start at cold most of the time. I checked fuel pressure at key on = 60 psi. When it starts and runs, it holds steady at 54 psi. When you shut it down it will hold 60 psi for about an hour or so, then it will bleed down. On restart after an hour or so, I turn the key but the pressure will remain at the bleed down psi. I attempt to restart and pressure goes down to 40 psi. The pump is running because i can hear it. If i release the fuel pressure at the fuel guage then turn the key, the pressure comes back to 60 psi and the truck will start. Does anyone have a clue? Thanks in advance, Trent

Key on, engine off, fuel pump running, pressure should be 60psi to 66psi so you're at the low end of the spec. Leakdown holding 60psi for an hour is great! However, if pressure does not increase from 40psi on restart, but does increase to 60psi or more after bleeding off the pressure, I would suspect a problem with the check valve in the fuel pump. There's only one way to know for sure, and that involves removing the fuel pump module to check the valve operation.

I was either headed for the pump or the regulator. This problem is just an odd duck. Typical 97 blazer problems. Thanks for the reply. I will post my results.