1998 chev 1500 hard starting when cold but starts fine after warming up changed plugs and sensors

Timing chain bro !

The first thing i would tey is changeing the fuel filter. Chevy has a problem with the design from the fuel pump to the fuel inlet on the intake manifold. What they did it is back up the power supply to the fuel pump from the fuel relay and split the curicut and ran the back up through the oil pressure sending unit . So even if the relay went bad while driveing the fuel pump would still get power and the truck wouldn't die on the road its a saftey thing .But if the relay is bad then the engine needs to build up enough oil pressure to trip the oil sending unit to send power to the pump from cranking thus a long cranking time when cold . Change the fuel filter first it should be replaced every 4 to 5 years anyway . A nd if that dosn't fix it try the relay it should be behind a panal inside the glove box on your truck and if that dosn't work replace the oil pressure sending unit. One of these 3 things should work if the fuel pump is working correctly