i have a 2000 chevy silverado z71 with the 5.3. 160,000 miles on it. the issue is that sometimes it has problems starting. other times its fine. when it does start on first crank it starts and then almost dies but then recovers and runs fine. other times it wont start even after 3 cranks. hold the pedal to the floor and it starts right up. any ideas? replaced crank sensor,engine coolant sensor and fuel pump. fuel pump does run while trying to start. no codes in computer.

Pull the vacuum line of of the fuel pressure regulator. Its on the drivers side of the fuel rail about in the middle. If gas comes out replace it.

i have a 2000 chevy silverado z71 with the 5.3. 160,000 miles on it. the issue is that sometimes it has problems starting. other times its fine. when it does start on first crank it starts and then almost dies but then recovers and runs fine. other times it wont start even after 3 cranks. hold the pedal to the floor and it starts right up. any ideas? replaced crank sensor,engine coolant sensor and fuel pump. fuel pump does run while trying to start. no codes in computer.

if there are no codes this could be the fuel pressure being low..spec is 53to 62 psi key on engine off..if the fuel pressure drops off quickly then the fuel pump is most likely bad..

since this is only on cold start ,,, you could also have a bad ECT..did you replace the driverside coolant sensor next to #1 spark plug ?


your engine has a PCV ..this needs replacing..the hoses need to be checked with this as well..