Is there a way to test vacuum secondaries?

Besides crappy performance.

 

I am also curious about this. My car will only rev to about 4,000 rpms and won't go any higher.

 

seems like a normal problem is the secondaries get stuck shut. Go to FAQ page and see the linkage that controlls them and see if you can get the secondary butterfly to move by hand. If it is not stuck, it should work. There is also a way to check them by vac in the FSM but I am unsure of how it is done. Mine were stuck shut and I could get it to redline in first and second and once I switched to mech secondaries, there was a very large difference. Could also be a fuel or timing problem.