SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I recently bought a house and it has a rainbird irrigation system. All the zones work great, except 1 zone, no pressure. I thought it was a valve issue so I replaced it, but still the same. Found 1 sprinkler that was busted, fixed it and got a little better. Then I noticed all the other zones have about 5 sprinklers and the one I am having issues with has 13 pop up sprayers. Basicaly they pop up half way and has some spray but also pushing water out around the base of the shaft, if I pull them up all the way the base of the shaft doesn't leak. Except the sprinklers furthest away from the valve, they barely have any pressure. I am wondering if there are just too many sprinkler heads. I am new to irrigation systems so any info would be appreciated, thanks.