You should be able to verify that the secondaries are working by manually operating the throttle linkage and watching the linkage engage above 3800 or so. If it seems to engage consistently you're butterfly valves in the LIM may be gunked up and sticking sometimes. A cleaning of the LIM should help this out. Cracking the secondaries open about a 1/2 turn or more on the stop blt should help reduce gunk buildup and may provide a little better performance. Some have removed the secondaries altogether.
