2001 silverado 1500 ext cab 5.3 The truck is hard to start in the morning once it starts it stumbles then runs good. If I turn it off and start it again right away it runs good. After it sits after warming up. it takes forever to start. I have to turn it over 3-4 times. I changed the Fuel injector pressure regulator, changed the fuel tank pressure sensor. No change so my next move is to replace the fuel pump. any help before I drop $200 or more into a new pump

 

You need to check the fuel pressure to see if it is correct and if it is bleeding off. You description sounds like a bad pump,very common on these trucks. If you are getting the pump for 200.00 it must not be very good quality that should be a 400-600 pump. Remember you get what you pay for.

 

2 things i would check, #1 fuel pressure like stated above, #2 spark plugs.. if the plugs are in use beyond 100k miles, and theyre worn down to the point of having something crazy like .080 or .090" gap you will have an extremely hard cold start.
normally if its the fuel pump it would run bad in general (lack of power under heavy acceleration,stalling ect.) along with hard starting.
Its much cheaper to take extra time and test things than to start changing parts randomly untill its fixed.
If the plugs have been replaced recently, or you take a few out and they have the correct gap & arent worn down bad then rule those out and check other things.