rumbler46

Truck doesnt start sometimes, I can get it to start if I "prime" it (turn the key to on 3 times and the forth time to start) and it will start. Once it is started it runs rough almost like I am loosing vacuum pressure. I have been getting O2 sensor codes and changed out the O2 sensors, didnt matter. Here is what I have done:
new O2 sensors
new plugs
new wires
new fuel filter
checked fuel pressure (60+psi)

Only thing I can think of now is blocked catalytic converters. Please tell me there is something else!!!!!!!!

2000CAYukon

What does the fuel pressure do when you turn off the ignition? If it does not hold pressure, then it is most likely fuel pressure regulator or stuck poppet.

Do a search on "fuel pressure regulator" and you will see if is fairly common and results in hard starting especially when it sits for 30 minutes to an hour or more.

//2000CAYukon