GMC Jimmy Starting problems

When my 2001 GMC Jimmy sits for more than ten minutes, when I try to start it the starter cranks for about 5 seconds before it starts. If I let the fuel pump build up pressure first and the turn the starter it starts right up

I'd hook up a fuel pressure gage and watch bleed down pressure after pump shuts off- does it drop fast-- like 60 psi to 0 in less than 30 seconds? You may have a fuel leak where you can't see it- like in the tank.

Inspect the fuel pressure regulator too, remove the vacuum hose running to it and look for any fuel contamination IN the hose, if you see any replace the regulator.

The fuel pressure regulator is inside the plenum and does not have a vacuum line to it.

Check fuel pressure and leakdown: Ignition ON, engine OFF, fuel pump running: Pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the pump shuts off.

As brcidd mentioned, the leak could be in the tank.... or it could be in the plenum. A pressure and leakdown test will determine if there is a leak, it will not tell where it is. The fuel pump must be isolated from the system immediately after the pump pressurizes the system, (and shuts off) to determine if the leak is in the tank or in the plenum.

Oh I see, in that case I'm sorry for my mistake. I hope this problem gets fixed soon, I had a very similar problem and the it turned to be the fuel pump but I was advised to check the FPR that way.

Best regards,

Oscar.