hp 4200n printer stutters on print jobs occasionally

Our printer that we have “stutters” or more specifically prints two pages, stops then prints three pages, stops, etc. And prints about 20 pages in the time our other printer of the same network/make/model prints 45 pages. We have 4 printers total on this part of our network and two of them have this problem on occasion. The inconsistancy of the problem is what makes it hard for me to diagnose. The printer guy has came out twice to look at them and tells my boss there is nothing wrong with it. I use the printers around 10pm and when the printer is checked it is usually closer to the afternoon. I work in a time based environment so it is important to have all 4 printers printing as fast as they can, any ideas on a diagnosis?