You can also get a shop manual for the year of your car from Nissan. A little pricey but I hear they are good. I am getting mine in a week. Haynes is good if you have a 240 or 260 because it mostly covers them and gives you five or six pages in the back for a 280z called supplemental which is extremely vague. Mine hasn't been very helpful. Could be vacuum problems or it could be fuel. The vacum parts sit right in there with the fuel lines. The big one, the bcdd sits right on the throttle body. There are like three othere solenoids that control acceleration. Haynes shows only one of those.
I have the same problem. It is real bad until the car warms up but it never completely goes away. Among some other electrical repairs I am going to check the pressure regulator, I noticed some fluid at the vacuume line.