I can't tell what you mean by start and stop as in download goes to 0 K/s and then up again, or if it alternates between downloading and Connecting to v.w.x.y [z seconds]. For the first problem see this post for possible reasons that are in addition to dimagor's theory:

<http://www.gnutellaforums.com/showth...6533#post20041>

For the second problem, I think it has do with the sender's Upload window saying Transfer Interrupted numerous times for a file while the file downloads a small portion at a time automatically. Later LimeWire versions have this problem but I don't know if it got fixed in the 2.x versions. It seems that the Mac version has this problem more and you may be able to tell yourself. If the names of the files that are stopping and starting are cut off at 31 characters then it is likely that you are downloading from a Mac.

<http://www.gnutellaforums.com/showth...4737#post21833>