I have a 2001 Silverado with a 4.3 liter V6. It is hard to start (long turnover time) and has a little bit of a rough idle. I want to test the feul pressure with a test kit but I cannot for the life of me find the valve to hook up the kit. I have searched the feul line from the feul filter up to where I think it goes into the block up at the top near the air intake. If someone could post a picture that would be great, or at least point me in the right direction.

Thanks for any help, and I apologize if I used incorrect terminology or part names I'm kinda new to working on cars and trucks but I would like to learn some more.