Gary,
Wish I could be of more help but fuel injection is not something that I know a lot about. However the breaking up and losing power would sound almost as if you may not be getting the amount of fuel that you need at that RPM. Also if you have a weak ignition spark it could be to weak under power to ignite the fuel completely at that point. The guy's with fuel injection can tell you what fuel pressures to check for and what else to check. Also could timing be an issue?
Ron
