96 chevrolet blazer 4.3 when truck sits over night it cranks over for 3-6 seconds before starting. will start a little quicker if gas pedal is slightly pressed?

There are several common fixes for this problem. Fuel spider is one, fuel pressure regulator is another. However, the most common and likely is your fuel pump module assembly. The fuel pump has to be able to hold pressure from the fuel tank all the way to the regulator. It works just like a foot valve on a well. When it goes bad it let's the fuel in the lines & fuel filter bleed the fuel back to the tank when not in use.when you try to start it after it sits, the fuel has to flow all the way back to the engine. Although the fuel pump is the most expensive of these items, more often than not, that will fix it. Fuel filter should also be checked and replaced if installing a new pump.