99 Sierra has trouble during initial start up

my 99 sierra Z71 has 81k mi on it i bought used in jan it was fine until it hit about 80k it takes about 4 or 5 cranks before she'll start up witch bothers me took it too the dealer they said they replaced the fuel pump and that it was the problem well they succeded in putting me off till my limited warranty expired so i took a look to make sure the pump was replaced wich it was so i replaced the fuel filter still no fix i have limited experience with all of the electronics and sensors involved with efi but my next replacements i figure will be some type of sensors or valves also the battery is good and the starter sounds strong unless plugs or wires can cause this im thinking its with the fuel because it seems to have lost some power since i drove it off the lot thanks for reading any comments are appreciated

also for other newbies "sierra-problem" or other general thread topics are not specific enough to even attemp to read i have scoured the threads for a few hours and havent seen any other threads with the same problem so too get help fixing your problems and questions or to help others like me searching for already discussed topics give a more descriptive topic thanks

Semper Fi