I have been having a starting issue for a while and I am stumped. I have an 02 silverado 1500,5.3, Z71, LT. When I go to start the truck, it will crank over but will not start. I turn the ignition off and retry and it will start right up. But on very cold mornings or very hot days(after running the AC) It will take even longer to start. I have replaced the fuel pressure regulator, coolant temp sensor but to no avail. What is baffling me is right after I top off the tank, and go to start the truck it will start with no problems. The fuel pump is about 4 years old and I will hear it priming when I turn the key on. On very cold mornings, it will take about 4 tries before it finally starts, but even then it will buck for a bit before it evens out. Where do I go from here? thanks for any help. I forgot to add, it also has a new fuel filter.

 

Check your fuel pressure. The fuel pump could go bad in 4 yrs. They usually do if you buy one of the cheaper aftermarket pumps. It could also be the check valve in the fuel pump assembly.

 

Time for a genuine AC/delco fuel pump

 

When turning the key on, do you wait about 4 - 5 seconds for the dash lights to turn off before trying to start the motor? This method gives time for the fuel pump to pump the fuel to the motor. Modern cars and trucks have had this for a long time.

If you are doing this then I'd say its time for a new fuel pump.