1999 GMC Sierra 1500 - Hard to start - then dies

It won’t start. Driving home it slowly lost rpm and died. Let it sit for 15 min, started back up but had to do this about 10 times before I could get home. Sounds like it is flooded or chocked up. Might run 5 seconds then dies. I’ve replaced map, maf ,iac sensors. My fixd now says crankshaft position sensor.

Fuel pump.