Vortec 454 runs but has low power

[Mkop]

I have a 2000 GMC 2500 with a vortec 7.4L and it has a couple of problems.

1. I have to crank and crank and crank to get it started. Replaced fuel pump and fuel pressure regulator already. It starts good though if I don't drive it for a couple days, it will fire right off. I did some reading and am wondering if it could be injectors??

2. Once it is started it runs pretty rich and has no power for about the first minute and then it snaps out of it and takes off. It doesn't matter if I let it idle for the minute or if I drive it, it takes about that long to get any power out of it.

[davester]

maybe the injectors are leaking, so there's a bunch of fuel in the intake if the truck sits for a short while (where it evaporates after a few days) and takes a bit for that fuel to go through the engine.

 

I know for my '04 Sierra 6.0l engine, I can do a leakdown test on the injectors using Autogenuity, you (or a dealer) with a tech ii may be able to do something similar to see if your injectors are working reasonably.

 

You may also be able to tell a little bit by just seeing how the fuel pressure goes down after you turn off the engine (I'm not sure about this, as I don't know how the FPR works when the engine turns off and there's no vacuum anymore).