long crank, after engine sitting

Hey whats up I have a 2001 ls 3.9L V8. I just bought the vehicle and when I first start the engine in the morning or after sitting for awhile. It has a long crank brfore starting. Once it has started I can shut down the engine and it will restart like a new car no problems. I have replaced the both fuel pumps due to have a code for fuel pump circuit faluire. After testing circuit (okay) found fuel pump to have to much resistance. And talking to dealer and finding out was common problem, replaced both fuel pumps. Still have same problem after $600.00 later. replace fuel filter, plugs w/dealer plugs, and removed and cleaned ilde air control valve. Can use some help please.

Check the fuel pressure at the fuel rail just after turning the key to the run position. Is it within spec? Check fuel pressure with the car running also to see if it's within spec. If the fuel pressure is where it should be, you might have slightly leaky injectors that flood the cylinders after sitting a while. If the pressure is low, you might have a fuel line restriction or a bad fuel pressure regulator.

Also, pick up a bottle of fuel injector cleaner and run that through. I recommend a bottle of injector cleaner everytime you change your oil. It's amazing how many "problems" can be fixed and/or prevented with regular use of injector cleaner. They all seem to work well, regardless of brand or price.

It would also be worth monitoring the battery voltage while cranking. If it is dropping much below 10.8 volts while cranking, you might have a weak battery.

-Rod